Optic Atrophy
Optic Atrophy, Autosomal Dominant
Optic Atrophies, Hereditary
Atrophy
Optic Nerve
Genes, Dominant
Wolfram Syndrome
Pedigree
Optic Disk
Polycystic Kidney, Autosomal Dominant
Optic Atrophy, Hereditary, Leber
Muscular Atrophy
Optic Neuritis
Hereditary Sensory and Motor Neuropathy
Mutation
Optic Chiasm
Genetic Linkage
Retinal Ganglion Cells
Mutation, Missense
Papilledema
Optic Nerve Injuries
Muscular Atrophy, Spinal
Visual Acuity
Vision Disorders
Cerebellar Ataxia
Phenotype
Lod Score
TRPP Cation Channels
DNA, Mitochondrial
Retina
Blindness
Retinitis Pigmentosa
Genetic Heterogeneity
Chromosome Mapping
Cataract
Onchocerciasis, Ocular
Molecular Sequence Data
Codon, Nonsense
Diabetes Insipidus
Optic Lobe, Nonmammalian
Optic Neuropathy, Ischemic
Multiple System Atrophy
Glutarates
Fundus Oculi
Hearing Loss, Sensorineural
Haplotypes
Mitochondrial Diseases
Abnormalities, Multiple
Mitochondrial Proteins
Visual Fields
Family Health
Magnetic Resonance Imaging
Color Vision Defects
Mitochondrial Dynamics
Myoclonic Cerebellar Dyssynergia
Vision, Low
Base Sequence
Microcephaly
Spinal Muscular Atrophies of Childhood
Optics and Photonics
Optic Nerve Glioma
Mitochondria
Chromosomes, Human, Pair 3
Nerve Fibers
Genotype
Membrane Proteins
Evoked Potentials, Visual
Disease Models, Animal
Founder Effect
Olivopontocerebellar Atrophies
Point Mutation
Spinocerebellar Degenerations
Polycystic Kidney Diseases
CADASIL
Retinal Diseases
Genetic Testing
Heterozygote
Visual Field Tests
Optic Nerve Diseases
Penetrance
NADH Dehydrogenase
Age of Onset
Polymerase Chain Reaction
Eye Proteins
Intellectual Disability
Leigh Disease
Genetic Markers
Gyrate Atrophy
Exons
Amino Acid Sequence
Neurodegenerative Diseases
Dementia, Multi-Infarct
Spastic Paraplegia, Hereditary
Chromosomes, Human, Pair 2
Geographic Atrophy
Tomography, Optical Coherence
Coloboma
Frameshift Mutation
Brain
Gene Deletion
Hand Deformities, Congenital
Spinocerebellar Ataxias
A comprehensive survey of mutations in the OPA1 gene in patients with autosomal dominant optic atrophy. (1/62)
PURPOSE: To characterize the spectrum of mutations in the OPA1 gene in a large international panel of patients with autosomal dominant optic atrophy (adOA), to improve understanding of the range of functional deficits attributable to sequence variants in this gene, and to assess any genotype-phenotype correlations. METHODS: All 28 coding exons of OPA1, intron-exon splice sites, 273 bp 5' to exon 1, and two intronic regions with putative function were screened in 94 apparently unrelated white patients of European origin with adOA by single-strand conformational polymorphism (SSCP)-heteroduplex analysis and direct sequencing. Clinical data were collated, and putative mutations were tested for segregation in the respective families by SSCP analysis or direct sequencing and in 100 control chromosomes. Further characterization of selected splice site mutations was performed by RT-PCR of patient leukocyte RNA. Staining of mitochondria in leukocytes of patients and control subjects was undertaken to assess gross differences in morphology and cellular distribution. RESULTS: Twenty different mutations were detected, of which 14 were novel disease mutations (missense, nonsense, deletion-frameshift, and splice site alterations) and six were known mutations. Mutations were found in 44 (47%) of the 94 families included in the study. Ten new polymorphisms in the OPA1 gene were also identified. Mutations occur throughout the gene, with three clusters emerging: in the mitochondrial leader, in the highly conserved guanosine triphosphate (GTP)-binding domain, and in the -COOH terminus. Examination of leukocyte mitochondria from two unrelated patients with splice site mutations in OPA1 revealed no abnormalities of morphology or cellular distribution when compared with control individuals. CONCLUSIONS: This study describes 14 novel mutations in the OPA1 gene in patients with adOA, bringing the total number so far reported to 54. It is likely that many cases of adOA are due to mutations outside the coding region of OPA1 or to large-scale rearrangements. Evaluation of the mutation spectrum indicates more than one pathophysiological mechanism for adOA. Preliminary data suggests that phenotype-genotype correlation is complex, implying a role for other genetic modifying or environmental factors. No evidence was found of pathologic changes in leukocyte mitochondria of patients with adOA. (+info)Optic disc morphology of patients with OPA1 autosomal dominant optic atrophy. (2/62)
BACKGROUND/AIMS: Patients with autosomal dominant optic atrophy (ADOA) are genetically heterogeneous, but all have disc pallor. A degree of cupping in ADOA can make the distinction from normal tension glaucoma (NTG) clinically difficult. This study aimed to clarify the features of the optic nerve of patients with ADOA at the OPA1 locus. METHODS: 29 patients (58 eyes), from 12 families, were identified in a prospective observational study of patients with ADOA examined by a single observer between 1995 and 1998, in whom genetic analysis showed either evidence for linkage to chromosome 3q28 or mutations in the ADOA gene, OPA1. All of the patients had disc and fundal photographs available for retrospective analysis. Clinical data collected included disc appearance, intraocular pressure, Snellen visual acuity, Hardy-Rand-Rittler colour vision plates, and Humphrey 30-2 visual fields. RESULTS: Mean age at time of examination was 37 years and mean visual acuity was 6/24. Disc morphology showed temporal disc pallor in 30 eyes (52%) and total disc pallor in 28 eyes (48%). At least one disc showed a cup to disc ratio of more than 0.5 in 18 patients (28 discs, 48%). The temporal neuroretinal rim always showed pallor and shallow shelving (or saucerisation) was seen in 46 eyes (79%). Only 12 discs (21%) had deep excavation and baring of blood vessels. All of the patients had normal intraocular pressure and no family history of glaucoma. There was a temporal grey, pigmentary crescent in 12 patients (18 eyes, 31%) and peripapillary atrophy in 20 patients (40 eyes, 69%), but disc margin haemorrhages were not seen. There was no maculopathy or retinopathy. CONCLUSION: The optic disc morphology, described for the first time in this genetically homogeneous population of patients with OPA1 ADOA, shows a distinctive absence of a healthy neuroretinal rim and shallow saucerisation of the optic disc cup, with frequent peripapillary atrophy. (+info)The phenotype of normal tension glaucoma patients with and without OPA1 polymorphisms. (3/62)
AIM: Polymorphisms in OPA1, the gene responsible for autosomal dominant optic atrophy, were recently found to be strongly associated with normal tension glaucoma (NTG). The aim of this study was to determine whether OPA1 polymorphisms affect the phenotype of NTG patients. METHODS: A retrospective analysis was performed of 108 well characterised NTG patients who had been genotyped for OPA1 variations, and who had previously undergone automated perimetry and Heidelberg retina tomography (HRT). 25 NTG patients had the at-risk OPA1 genotype (IVS 8 +4 C/T; +32 T/C) and 83 NTG patients did not. Differences between groups were sought in a wide range of structural, psychophysical, and demographic factors. These included sex, age at diagnosis, family history of glaucoma, history of ischaemic risk factors and vasospasm, laterality of glaucoma, presenting and highest diurnal intraocular pressure (IOP), initial cup-disc (CD) ratio, baseline visual field global indices, and optic disc parameters as measured by HRT. For a subgroup of patients with at least 5 years of follow up and 10 visual field tests, pointwise linear regression analysis (PROGRESSOR for Windows software) was applied to the visual field series. RESULTS: There was no significant difference in the two groups with respect to sex, age at diagnosis, family history of glaucoma, history of ischaemic risk factors and vasospasm, or laterality of glaucoma. The comparison of IOP, CD ratio and visual field global indices, MD and CPSD in the two groups showed no significant difference. There were no differences in the mean values for any of the HRT parameters analysed. For the subgroup of patients with at least 5 years of follow up, there was also no significant difference in the number of patients with progressing locations, the mean number of progressing locations per subject, the mean slope of the progressing locations or the mean slope for whole visual field. CONCLUSIONS: The absence of phenotypic differences in normal tension glaucoma patients with and without the OPA1 polymorphisms IVS 8 +4 C/T; +32 T/C suggest that these OPA1 polymorphisms do not underlie any major phenotypic diversity in these patients. (+info)Gene structure and chromosomal localization of mouse Opa1 : its exclusion from the Bst locus. (4/62)
BACKGROUND: Autosomal dominant optic atrophy type 1 (DOA) is the most common form of hereditary optic atrophy in human. We have previously identified the OPA1 gene and shown that it was mutated in patients with DOA. OPA1 is a novel member of the dynamin GTPase family that play a role in the distribution of the mitochondrial network. The Bst (belly spot and tail) mutant mice show atrophy of the optic nerves and previous mapping data raise the possibility that Bst and OPA1 are orthologs. In order to analyse the Bst mouse as a model for DOA, we therefore characterized mouse Opa1 and evaluated it as a candidate for the Bst mutant mouse. RESULTS: Comparison of mouse and human OPA1 sequences revealed 88% and 97% identity at the nucleotide and amino acid levels, respectively. Presence of alternatively spliced mRNAs as seen in human was conserved in the mouse. Screening of the whole mRNA coding sequence and of the 31 exons of Opa1 did not reveal any mutation in Bst. Using a radiation hybrid panel (T31), we mapped Opa1 to chromosome 16 between genetic markers D16Mit3 and D16Mit124, which is 10 cM centromeric to the Bst locus. CONCLUSION: On the basis of these results we conclude that Opa1 and Bst are distinct genes and that the Bst mouse is not the mouse model for DOA. (+info)Developmental expression profile of the optic atrophy gene product: OPA1 is not localized exclusively in the mammalian retinal ganglion cell layer. (5/62)
PURPOSE: Autosomal dominant optic atrophy (ADOA) is characterized by primary degeneration of retinal ganglion cells and atrophy of the optic nerve. The OPA1 gene encodes a 960-amino-acid protein. In the current study the temporal and spatial localization of OPA1 were examined in developing and adult murine ocular tissues and the adult human eye. Because the Bst/+ mouse has been postulated as a model of ADOA, the mOPA1 expression in the Bst/+ retina was also examined. METHODS: A polyclonal antibody generated against a C-terminal peptide of OPA1 was used to assess by immunohistochemistry the expression of mOPA1 in the wild-type embryonic and postnatal mouse ocular tissues and the Bst/+ retina. Western blot analyses of total proteins from a panel of adult human tissues were used to examine the expression of human OPA1, and spatial localization was assessed by immunohistochemistry. RESULTS: The ocular expression of mOPA1 begins at E15 in the inner retina in a location corresponding to that of the subsequently developing ganglion cell layer (GCL) and peaks between postnatal day (P)0 and P1 in the retina and the optic nerve. There is a sharp decline in mOPA1 expression after P2, but it is expressed at a basal level until at least P12 in the GCL, inner plexiform layer (IPL), and inner nuclear layer (INL) of the retina as well as in the optic nerve. In the adult Bst/+ retina, mOPA1 is strongly expressed in the GCL and IPL and weakly in the INL. In the adult human eye, OPA1 is expressed in the GCL, IPL, INL, and outer plexiform layer (OPL) of the retina and in the optic nerve, where it is observed only in the myelinated region. CONCLUSIONS: OPA1 is not restricted to the GCL of the mammalian retina, and its expression extends into the IPL, INL, and OPL. OPA1 is distinctly expressed in the myelinated region beyond the lamina cribrosa in the human optic nerve, whereas its expression is weaker in the mouse optic nerve. In the Bst/+ mouse retina, despite the structural defects, mOPA1 expression is comparable to that observed in the wild-type adult mouse retina. These observations suggest a wider role for OPA1 than previously anticipated. (+info)OPA1, the disease gene for autosomal dominant optic atrophy, is specifically expressed in ganglion cells and intrinsic neurons of the retina. (6/62)
PURPOSE: Autosomal dominant optic atrophy is a hereditary disorder characterized by progressive loss of vision and caused by mutations in a dynamin-related gene, OPA1, which translates into a protein with a mitochondrial leader sequence. In this study the OPA1 gene and its protein were localized in the rat and mouse retina, and its rat orthologue, rOpa1, was identified. METHODS: The rOpa1 cDNA was isolated by using reverse transcribed cDNA from total RNA obtained from a rat retinal ganglion cell line. The spatial and temporal expression patterns of OPA1 and its gene product were investigated by RNA in situ hybridization and immunohistochemistry in mouse and rat retinas. To characterize further the OPA1-positive neurons, retinal ganglion cells were retrogradely labeled by an immunogold fluorescent tracer or double labeled with OPA1 and choline acetyltransferase or calbindin antibodies. RESULTS: Protein sequence alignment revealed a 96% identity between rat and human OPA1 mRNA. OPA1 expression was found as early as postnatal day 3 in the developing rodent retina. In the mature retina, the OPA1 gene and its protein were found not only in retinal ganglion cells, but also in starburst amacrine cells and horizontal cells, both of which are involved in lateral signal processing within the retina. However, OPA1 was absent from mitochondria rich nerve fibers and photoreceptor indicating a specific role for OPA1 in signal processing rather than in the requirement of mitochondrial energy supply in the retina. CONCLUSIONS: The data suggest an important and specific function of the OPA1 protein, not only in the optic nerve forming ganglion cells but also in the intrinsic signal processing of the inner retina. (+info)Autosomal dominant optic atrophy associated with hearing impairment and impaired glucose regulation caused by a missense mutation in the WFS1 gene. (7/62)
Autosomal dominant optic atrophy (ADOA) is genetically heterogeneous, with OPA1 on 3q28 being the most prevalently mutated gene. Additional loci are OPA3, OPA4, and OPA5, located at 19q13.2, 18q12.2, and 22q12.1-q13.1, respectively. Mutations in the WFS1 gene, at 4p16.3, are associated with either optic atrophy (OA) as part of the autosomal recessive Wolfram syndrome or with autosomal dominant progressive low frequency sensorineural hearing loss (LFSNHL) without any ophthalmological abnormalities. Linkage and sequence mutation analyses of the ADOA candidate genes OPA1, OPA3, OPA4, and OPA5, including the genes WFS1, GJB2, and GJB6 associated with recessive inherited OA or dominant LFSNHL, were performed. We identified one novel WFS1 missense mutation E864K, c.2590G-->A in exon 8 that co-segregates with ADOA combined with hearing impairment and impaired glucose regulation. This is the first example of autosomal dominant optic atrophy and hearing loss associated with a WFS1 mutation, supporting the notion that mutations in WFS1 as well as in OPA1 may lead to ADOA combined with impaired hearing. (+info)Mitochondrial dynamics and disease, OPA1. (8/62)
The mitochondria are dynamic organelles that constantly fuse and divide. An equilibrium between fusion and fission controls the morphology of the mitochondria, which appear as dots or elongated tubules depending the prevailing force. Characterization of the components of the fission and fusion machineries has progressed considerably, and the emerging question now is what role mitochondrial dynamics play in mitochondrial and cellular functions. Its importance has been highlighted by the discovery that two human diseases are caused by mutations in the two mitochondrial pro-fusion genes, MFN2 and OPA1. This review will focus on data concerning the function of OPA1, mutations in which cause optic atrophy, with respect to the underlying pathophysiological processes. (+info)Optic atrophy is a medical term that refers to the degeneration and shrinkage (atrophy) of the optic nerve, which transmits visual information from the eye to the brain. This condition can result in various vision abnormalities, including loss of visual acuity, color vision deficiencies, and peripheral vision loss.
Optic atrophy can occur due to a variety of causes, such as:
* Traumatic injuries to the eye or optic nerve
* Glaucoma
* Optic neuritis (inflammation of the optic nerve)
* Ischemic optic neuropathy (reduced blood flow to the optic nerve)
* Compression or swelling of the optic nerve
* Hereditary or congenital conditions affecting the optic nerve
* Toxins and certain medications that can damage the optic nerve.
The diagnosis of optic atrophy typically involves a comprehensive eye examination, including visual acuity testing, refraction assessment, slit-lamp examination, and dilated funduscopic examination to evaluate the health of the optic nerve. In some cases, additional diagnostic tests such as visual field testing, optical coherence tomography (OCT), or magnetic resonance imaging (MRI) may be necessary to confirm the diagnosis and determine the underlying cause.
There is no specific treatment for optic atrophy, but addressing the underlying cause can help prevent further damage to the optic nerve. In some cases, vision rehabilitation may be recommended to help patients adapt to their visual impairment.
Autosomal dominant optic atrophy (ADOA) is a genetic disorder that affects the optic nerve, which transmits visual information from the eye to the brain. The term "optic atrophy" refers to degeneration or damage to the optic nerve. In ADOA, this condition is inherited in an autosomal dominant manner, meaning that only one copy of the mutated gene, located on one of the autosomal chromosomes (not a sex chromosome), needs to be present for the individual to develop the disorder.
The most common form of ADOA is caused by mutations in the OPA1 gene, which provides instructions for making a protein involved in the maintenance of mitochondria, the energy-producing structures in cells. The exact role of this protein in optic nerve function is not fully understood, but it is thought to play a critical role in maintaining the health and function of retinal ganglion cells, which are the neurons that make up the optic nerve.
In ADOA, mutations in the OPA1 gene lead to progressive degeneration of retinal ganglion cells and their axons (nerve fibers) within the optic nerve. This results in decreased visual acuity, color vision deficits, and a characteristic visual field defect called centrocecal scotoma, which is an area of blindness near the center of the visual field. The onset and severity of these symptoms can vary widely among individuals with ADOA.
It's important to note that medical definitions may contain complex terminology. In simpler terms, autosomal dominant optic atrophy (ADOA) is a genetic condition affecting the optic nerve, leading to decreased visual acuity and other vision problems due to degeneration of retinal ganglion cells. The disorder is inherited in an autosomal dominant manner, meaning only one copy of the mutated gene is needed for the individual to develop ADOA.
Hereditary optic atrophies (HOAs) are a group of genetic disorders that cause degeneration of the optic nerve, leading to vision loss. The optic nerve is responsible for transmitting visual information from the eye to the brain. In HOAs, this nerve degenerates over time, resulting in decreased visual acuity, color vision deficits, and sometimes visual field defects.
There are several types of HOAs, including dominant optic atrophy (DOA), Leber hereditary optic neuropathy (LHON), autosomal recessive optic atrophy (AROA), and Wolfram syndrome. Each type has a different inheritance pattern and is caused by mutations in different genes.
DOA is the most common form of HOA and is characterized by progressive vision loss that typically begins in childhood or early adulthood. It is inherited in an autosomal dominant manner, meaning that a child has a 50% chance of inheriting the disease-causing mutation from an affected parent.
LHON is a mitochondrial disorder that primarily affects males and is characterized by sudden, severe vision loss that typically occurs in young adulthood. It is caused by mutations in the mitochondrial DNA and is inherited maternally.
AROA is a rare form of HOA that is inherited in an autosomal recessive manner, meaning that both copies of the gene must be mutated to cause the disease. It typically presents in infancy or early childhood with progressive vision loss.
Wolfram syndrome is a rare genetic disorder that affects multiple organs, including the eyes, ears, and endocrine system. It is characterized by diabetes insipidus, diabetes mellitus, optic atrophy, and hearing loss. It is inherited in an autosomal recessive manner.
There is currently no cure for HOAs, but treatments such as low-vision aids and rehabilitation may help to manage the symptoms. Research is ongoing to develop new therapies for these disorders.
Atrophy is a medical term that refers to the decrease in size and wasting of an organ or tissue due to the disappearance of cells, shrinkage of cells, or decreased number of cells. This process can be caused by various factors such as disuse, aging, degeneration, injury, or disease.
For example, if a muscle is immobilized for an extended period, it may undergo atrophy due to lack of use. Similarly, certain medical conditions like diabetes, cancer, and heart failure can lead to the wasting away of various tissues and organs in the body.
Atrophy can also occur as a result of natural aging processes, leading to decreased muscle mass and strength in older adults. In general, atrophy is characterized by a decrease in the volume or weight of an organ or tissue, which can have significant impacts on its function and overall health.
The optic nerve, also known as the second cranial nerve, is the nerve that transmits visual information from the retina to the brain. It is composed of approximately one million nerve fibers that carry signals related to vision, such as light intensity and color, from the eye's photoreceptor cells (rods and cones) to the visual cortex in the brain. The optic nerve is responsible for carrying this visual information so that it can be processed and interpreted by the brain, allowing us to see and perceive our surroundings. Damage to the optic nerve can result in vision loss or impairment.
Dominant genes refer to the alleles (versions of a gene) that are fully expressed in an individual's phenotype, even if only one copy of the gene is present. In dominant inheritance patterns, an individual needs only to receive one dominant allele from either parent to express the associated trait. This is in contrast to recessive genes, where both copies of the gene must be the recessive allele for the trait to be expressed. Dominant genes are represented by uppercase letters (e.g., 'A') and recessive genes by lowercase letters (e.g., 'a'). If an individual inherits one dominant allele (A) from either parent, they will express the dominant trait (A).
Wolfram Syndrome is a rare, progressive, genetic disorder that affects multiple organ systems, particularly the eyes, brain, endocrine system, and hearing. It is characterized by the combination of several features including diabetes insipidus (DI), diabetes mellitus (DM), optic nerve atrophy, and various neurological symptoms. The onset of this syndrome typically occurs in childhood.
The two major types of Wolfram Syndrome are WFS1 and WFS2, with WFS1 being the most common form. They are caused by mutations in different genes (WFS1 and CISD2 respectively), both of which play a role in maintaining the health of cells in the body, particularly those in the pancreas, eyes, and ears.
The symptoms of Wolfram Syndrome can vary widely among affected individuals, but often include:
- Diabetes insipidus (DI): This is characterized by excessive thirst and urination due to problems with the body's regulation of fluids.
- Diabetes mellitus (DM): This type of diabetes results from issues with insulin production or usage, leading to high blood sugar levels.
- Optic nerve atrophy: This can cause vision loss, typically starting in early childhood and progressing over time.
- Neurological symptoms: These may include hearing loss, problems with balance and coordination, difficulty swallowing, and neuropsychiatric issues such as depression and anxiety.
Currently, there is no cure for Wolfram Syndrome, and treatment primarily focuses on managing the individual symptoms of the disorder.
I must clarify that the term "pedigree" is not typically used in medical definitions. Instead, it is often employed in genetics and breeding, where it refers to the recorded ancestry of an individual or a family, tracing the inheritance of specific traits or diseases. In human genetics, a pedigree can help illustrate the pattern of genetic inheritance in families over multiple generations. However, it is not a medical term with a specific clinical definition.
GTP (Guanosine Triphosphate) Phosphohydrolases are a group of enzymes that catalyze the hydrolysis of GTP to GDP (Guanosine Diphosphate) and inorganic phosphate. This reaction plays a crucial role in regulating various cellular processes, including signal transduction pathways, protein synthesis, and vesicle trafficking.
The human genome encodes several different types of GTP Phosphohydrolases, such as GTPase-activating proteins (GAPs), GTPase effectors, and G protein-coupled receptors (GPCRs). These enzymes share a common mechanism of action, in which they utilize the energy released from GTP hydrolysis to drive conformational changes that enable them to interact with downstream effector molecules and modulate their activity.
Dysregulation of GTP Phosphohydrolases has been implicated in various human diseases, including cancer, neurodegenerative disorders, and infectious diseases. Therefore, understanding the structure, function, and regulation of these enzymes is essential for developing novel therapeutic strategies to target these conditions.
The optic disk, also known as the optic nerve head, is the point where the optic nerve fibers exit the eye and transmit visual information to the brain. It appears as a pale, circular area in the back of the eye, near the center of the retina. The optic disk has no photoreceptor cells (rods and cones), so it is insensitive to light. It is an important structure to observe during eye examinations because changes in its appearance can indicate various ocular diseases or conditions, such as glaucoma, optic neuritis, or papilledema.
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a genetic disorder characterized by the growth of multiple cysts in the kidneys. These cysts are fluid-filled sacs that can vary in size and can multiply, leading to enlarged kidneys. The increased size and number of cysts can eventually result in reduced kidney function, high blood pressure, and potentially kidney failure.
ADPKD is an autosomal dominant disorder, meaning it only requires one copy of the altered gene (from either the mother or father) to have the disease. Each child of an affected individual has a 50% chance of inheriting the mutated gene. The two genes most commonly associated with ADPKD are PKD1 and PKD2, located on chromosomes 16 and 4, respectively.
Symptoms can vary widely among individuals with ADPKD, but they often include high blood pressure, back or side pain, headaches, increased abdominal size due to enlarged kidneys, blood in the urine, and kidney failure. Other complications may include cysts in the liver, pancreas, and/or brain (berries aneurysms).
Early diagnosis and management of ADPKD can help slow down disease progression and improve quality of life. Treatment typically includes controlling high blood pressure, managing pain, monitoring kidney function, and addressing complications as they arise. In some cases, dialysis or a kidney transplant may be necessary if kidney failure occurs.
Hereditary Optic Atrophy, Leber type (LOA) is a mitochondrial DNA-associated inherited condition that primarily affects the optic nerve and leads to vision loss. It is characterized by the degeneration of retinal ganglion cells and their axons, which make up the optic nerve. This results in bilateral, painless, and progressive visual deterioration, typically beginning in young adulthood (14-35 years).
Leber's hereditary optic atrophy is caused by mutations in the mitochondrial DNA (mtDNA) gene MT-ND4 or MT-ND6. The condition follows a maternal pattern of inheritance, meaning that it is passed down through the mother's lineage.
The onset of LOA usually occurs in one eye first, followed by the second eye within weeks to months. Central vision is initially affected, leading to blurriness and loss of visual acuity. Color vision may also be impaired. The progression of the condition generally stabilizes after a few months, but complete recovery of vision is unlikely.
Currently, there is no cure for Leber's hereditary optic atrophy. Treatment focuses on managing symptoms and providing visual rehabilitation to help affected individuals adapt to their visual impairment.
Muscular atrophy is a condition characterized by a decrease in the size and mass of muscles due to lack of use, disease, or injury. This occurs when there is a disruption in the balance between muscle protein synthesis and degradation, leading to a net loss of muscle proteins. There are two main types of muscular atrophy:
1. Disuse atrophy: This type of atrophy occurs when muscles are not used or are immobilized for an extended period, such as after an injury, surgery, or prolonged bed rest. In this case, the nerves that control the muscles may still be functioning properly, but the muscles themselves waste away due to lack of use.
2. Neurogenic atrophy: This type of atrophy is caused by damage to the nerves that supply the muscles, leading to muscle weakness and wasting. Conditions such as amyotrophic lateral sclerosis (ALS), spinal cord injuries, and peripheral neuropathies can cause neurogenic atrophy.
In both cases, the affected muscles may become weak, shrink in size, and lose their tone and mass. Treatment for muscular atrophy depends on the underlying cause and may include physical therapy, exercise, and medication to manage symptoms and improve muscle strength and function.
Optic neuritis is a medical condition characterized by inflammation and damage to the optic nerve, which transmits visual information from the eye to the brain. This condition can result in various symptoms such as vision loss, pain with eye movement, color vision disturbances, and pupillary abnormalities. Optic neuritis may occur in isolation or be associated with other underlying medical conditions, including multiple sclerosis, neuromyelitis optica, and autoimmune disorders. The diagnosis typically involves a comprehensive eye examination, including visual acuity testing, dilated funduscopic examination, and possibly imaging studies like MRI to evaluate the optic nerve and brain. Treatment options may include corticosteroids or other immunomodulatory therapies to reduce inflammation and prevent further damage to the optic nerve.
Hereditary Sensory and Motor Neuropathy (HSMN) is a group of inherited disorders that affect the peripheral nerves, which are the nerves outside the brain and spinal cord. These nerves transmit information between the brain and muscles, as well as sensations such as touch, pain, heat, and cold.
HSMN is characterized by progressive degeneration of these peripheral nerves, leading to muscle weakness, numbness, and tingling sensations, particularly in the hands and feet. The condition can also affect the autonomic nervous system, which controls involuntary functions such as heart rate, blood pressure, and digestion.
HSMN is caused by genetic mutations that are inherited from one or both parents. There are several types of HSMN, each with its own specific symptoms, severity, and pattern of inheritance. The most common form is Charcot-Marie-Tooth disease (CMT), which affects both motor and sensory nerves.
Treatment for HSMN typically focuses on managing the symptoms and preventing complications. This may include physical therapy, bracing or orthopedic surgery to support weakened muscles, pain management, and lifestyle modifications such as avoiding activities that aggravate symptoms. There is currently no cure for HSMN, but ongoing research is aimed at developing new treatments and therapies to slow or halt the progression of the disease.
A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.
The optic chiasm is a structure in the brain where the optic nerves from each eye meet and cross. This allows for the integration of visual information from both eyes into the brain's visual cortex, creating a single, combined image of the visual world. The optic chiasm plays an important role in the processing of visual information and helps to facilitate depth perception and other complex visual tasks. Damage to the optic chiasm can result in various visual field deficits, such as bitemporal hemianopsia, where there is a loss of vision in the outer halves (temporal fields) of both eyes' visual fields.
Genetic linkage is the phenomenon where two or more genetic loci (locations on a chromosome) tend to be inherited together because they are close to each other on the same chromosome. This occurs during the process of sexual reproduction, where homologous chromosomes pair up and exchange genetic material through a process called crossing over.
The closer two loci are to each other on a chromosome, the lower the probability that they will be separated by a crossover event. As a result, they are more likely to be inherited together and are said to be linked. The degree of linkage between two loci can be measured by their recombination frequency, which is the percentage of meiotic events in which a crossover occurs between them.
Linkage analysis is an important tool in genetic research, as it allows researchers to identify and map genes that are associated with specific traits or diseases. By analyzing patterns of linkage between markers (identifiable DNA sequences) and phenotypes (observable traits), researchers can infer the location of genes that contribute to those traits or diseases on chromosomes.
Retinal Ganglion Cells (RGCs) are a type of neuron located in the innermost layer of the retina, the light-sensitive tissue at the back of the eye. These cells receive visual information from photoreceptors (rods and cones) via intermediate cells called bipolar cells. RGCs then send this visual information through their long axons to form the optic nerve, which transmits the signals to the brain for processing and interpretation as vision.
There are several types of RGCs, each with distinct morphological and functional characteristics. Some RGCs are specialized in detecting specific features of the visual scene, such as motion, contrast, color, or brightness. The diversity of RGCs allows for a rich and complex representation of the visual world in the brain.
Damage to RGCs can lead to various visual impairments, including loss of vision, reduced visual acuity, and altered visual fields. Conditions associated with RGC damage or degeneration include glaucoma, optic neuritis, ischemic optic neuropathy, and some inherited retinal diseases.
DNA Mutational Analysis is a laboratory test used to identify genetic variations or changes (mutations) in the DNA sequence of a gene. This type of analysis can be used to diagnose genetic disorders, predict the risk of developing certain diseases, determine the most effective treatment for cancer, or assess the likelihood of passing on an inherited condition to offspring.
The test involves extracting DNA from a patient's sample (such as blood, saliva, or tissue), amplifying specific regions of interest using polymerase chain reaction (PCR), and then sequencing those regions to determine the precise order of nucleotide bases in the DNA molecule. The resulting sequence is then compared to reference sequences to identify any variations or mutations that may be present.
DNA Mutational Analysis can detect a wide range of genetic changes, including single-nucleotide polymorphisms (SNPs), insertions, deletions, duplications, and rearrangements. The test is often used in conjunction with other diagnostic tests and clinical evaluations to provide a comprehensive assessment of a patient's genetic profile.
It is important to note that not all mutations are pathogenic or associated with disease, and the interpretation of DNA Mutational Analysis results requires careful consideration of the patient's medical history, family history, and other relevant factors.
A missense mutation is a type of point mutation in which a single nucleotide change results in the substitution of a different amino acid in the protein that is encoded by the affected gene. This occurs when the altered codon (a sequence of three nucleotides that corresponds to a specific amino acid) specifies a different amino acid than the original one. The function and/or stability of the resulting protein may be affected, depending on the type and location of the missense mutation. Missense mutations can have various effects, ranging from benign to severe, depending on the importance of the changed amino acid for the protein's structure or function.
Papilledema is a medical term that refers to swelling of the optic nerve head, also known as the disc, which is the point where the optic nerve enters the back of the eye (the retina). This swelling can be caused by increased pressure within the skull, such as from brain tumors, meningitis, or idiopathic intracranial hypertension. Papilledema is usually detected through a routine eye examination and may be accompanied by symptoms such as headaches, visual disturbances, and nausea. If left untreated, papilledema can lead to permanent vision loss.
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
Recessive genes refer to the alleles (versions of a gene) that will only be expressed when an individual has two copies of that particular allele, one inherited from each parent. If an individual inherits one recessive allele and one dominant allele for a particular gene, the dominant allele will be expressed and the recessive allele will have no effect on the individual's phenotype (observable traits).
Recessive genes can still play a role in determining an individual's genetic makeup and can be passed down through generations even if they are not expressed. If two carriers of a recessive gene have children, there is a 25% chance that their offspring will inherit two copies of the recessive allele and exhibit the associated recessive trait.
Examples of genetic disorders caused by recessive genes include cystic fibrosis, sickle cell anemia, and albinism.
Optic nerve injuries refer to damages or trauma inflicted on the optic nerve, which is a crucial component of the visual system. The optic nerve transmits visual information from the retina to the brain, enabling us to see. Injuries to the optic nerve can result in various visual impairments, including partial or complete vision loss, decreased visual acuity, changes in color perception, and reduced field of view.
These injuries may occur due to several reasons, such as:
1. Direct trauma to the eye or head
2. Increased pressure inside the eye (glaucoma)
3. Optic neuritis, an inflammation of the optic nerve
4. Ischemia, or insufficient blood supply to the optic nerve
5. Compression from tumors or other space-occupying lesions
6. Intrinsic degenerative conditions affecting the optic nerve
7. Toxic exposure to certain chemicals or medications
Optic nerve injuries are diagnosed through a comprehensive eye examination, including visual acuity testing, slit-lamp examination, dilated fundus exam, and additional diagnostic tests like optical coherence tomography (OCT) and visual field testing. Treatment options vary depending on the cause and severity of the injury but may include medications, surgery, or vision rehabilitation.
Spinal muscular atrophy (SMA) is a genetic disorder that affects the motor neurons in the spinal cord, leading to muscle weakness and atrophy. It is caused by a mutation in the survival motor neuron 1 (SMN1) gene, which results in a deficiency of SMN protein necessary for the survival of motor neurons.
There are several types of SMA, classified based on the age of onset and severity of symptoms. The most common type is type 1, also known as Werdnig-Hoffmann disease, which presents in infancy and is characterized by severe muscle weakness, hypotonia, and feeding difficulties. Other types include type 2 (intermediate SMA), type 3 (Kugelberg-Welander disease), and type 4 (adult-onset SMA).
The symptoms of SMA may include muscle wasting, fasciculations, weakness, hypotonia, respiratory difficulties, and mobility impairment. The diagnosis of SMA typically involves genetic testing to confirm the presence of a mutation in the SMN1 gene. Treatment options for SMA may include medications, physical therapy, assistive devices, and respiratory support.
Visual acuity is a measure of the sharpness or clarity of vision. It is usually tested by reading an eye chart from a specific distance, such as 20 feet (6 meters). The standard eye chart used for this purpose is called the Snellen chart, which contains rows of letters that decrease in size as you read down the chart.
Visual acuity is typically expressed as a fraction, with the numerator representing the testing distance and the denominator indicating the smallest line of type that can be read clearly. For example, if a person can read the line on the eye chart that corresponds to a visual acuity of 20/20, it means they have normal vision at 20 feet. If their visual acuity is 20/40, it means they must be as close as 20 feet to see what someone with normal vision can see at 40 feet.
It's important to note that visual acuity is just one aspect of overall vision and does not necessarily reflect other important factors such as peripheral vision, depth perception, color vision, or contrast sensitivity.
Vision disorders refer to a wide range of conditions that affect the visual system and result in various symptoms, such as blurry vision, double vision, distorted vision, impaired depth perception, and difficulty with visual tracking or focusing. These disorders can be categorized into several types, including:
1. Refractive errors: These occur when the shape of the eye prevents light from focusing directly on the retina, resulting in blurry vision. Examples include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia (age-related loss of near vision).
2. Strabismus: Also known as crossed eyes or walleye, strabismus is a misalignment of the eyes where they point in different directions, which can lead to double vision or loss of depth perception.
3. Amblyopia: Often called lazy eye, amblyopia is a condition where one eye has reduced vision due to lack of proper visual development during childhood. It may be caused by strabismus, refractive errors, or other factors that interfere with normal visual development.
4. Accommodative disorders: These involve problems with the focusing ability of the eyes, such as convergence insufficiency (difficulty focusing on close objects) and accommodative dysfunction (inability to maintain clear vision at different distances).
5. Binocular vision disorders: These affect how the eyes work together as a team, leading to issues like poor depth perception, eye strain, and headaches. Examples include convergence insufficiency, divergence excess, and suppression.
6. Ocular motility disorders: These involve problems with eye movement, such as nystagmus (involuntary eye movements), strabismus, or restricted extraocular muscle function.
7. Visual processing disorders: These affect the brain's ability to interpret and make sense of visual information, even when the eyes themselves are healthy. Symptoms may include difficulty with reading, recognizing shapes and objects, and understanding spatial relationships.
8. Low vision: This term refers to significant visual impairment that cannot be fully corrected with glasses, contact lenses, medication, or surgery. It includes conditions like macular degeneration, diabetic retinopathy, glaucoma, and cataracts.
9. Blindness: Complete loss of sight in both eyes, which can be caused by various factors such as injury, disease, or genetic conditions.
Cerebellar ataxia is a type of ataxia, which refers to a group of disorders that cause difficulties with coordination and movement. Cerebellar ataxia specifically involves the cerebellum, which is the part of the brain responsible for maintaining balance, coordinating muscle movements, and regulating speech and eye movements.
The symptoms of cerebellar ataxia may include:
* Unsteady gait or difficulty walking
* Poor coordination of limb movements
* Tremors or shakiness, especially in the hands
* Slurred or irregular speech
* Abnormal eye movements, such as nystagmus (rapid, involuntary movement of the eyes)
* Difficulty with fine motor tasks, such as writing or buttoning a shirt
Cerebellar ataxia can be caused by a variety of underlying conditions, including:
* Genetic disorders, such as spinocerebellar ataxia or Friedreich's ataxia
* Brain injury or trauma
* Stroke or brain hemorrhage
* Infections, such as meningitis or encephalitis
* Exposure to toxins, such as alcohol or certain medications
* Tumors or other growths in the brain
Treatment for cerebellar ataxia depends on the underlying cause. In some cases, there may be no cure, and treatment is focused on managing symptoms and improving quality of life. Physical therapy, occupational therapy, and speech therapy can help improve coordination, balance, and communication skills. Medications may also be used to treat specific symptoms, such as tremors or muscle spasticity. In some cases, surgery may be recommended to remove tumors or repair damage to the brain.
A phenotype is the physical or biochemical expression of an organism's genes, or the observable traits and characteristics resulting from the interaction of its genetic constitution (genotype) with environmental factors. These characteristics can include appearance, development, behavior, and resistance to disease, among others. Phenotypes can vary widely, even among individuals with identical genotypes, due to differences in environmental influences, gene expression, and genetic interactions.
A LOD (Logarithm of Odds) score is not a medical term per se, but rather a statistical concept that is used in genetic research and linkage analysis to determine the likelihood of a gene or genetic marker being linked to a particular disease or trait. The LOD score compares the odds of observing the pattern of inheritance of a genetic marker in a family if the marker is linked to the disease, versus the odds if the marker is not linked. A LOD score of 3 or higher is generally considered evidence for linkage, while a score of -2 or lower is considered evidence against linkage.
Transient Receptor Potential (TRP) channels are a type of ion channel that play a crucial role in various physiological processes, including sensory perception, cellular signaling, and regulation of intracellular calcium levels. TRPP cation channels, also known as TRPP subfamily or polycystin channels, are a specific subgroup within the TRP channel family.
TRPP channels consist of two members: TRPP1 (also known as PKD1 or polycystin-1) and TRPP2 (also known as PKD2 or polycystin-2). These channels form heterodimers, meaning they are composed of two different subunits that come together to create a functional channel.
TRPP channels are primarily located in the primary cilium, a hair-like structure protruding from the cell surface, and in the endoplasmic reticulum (ER), an intracellular organelle involved in protein folding and calcium storage. They function as mechano- and chemosensors, responding to various stimuli such as mechanical forces, changes in temperature, pH, or chemical ligands.
TRPP channels are particularly important in the context of renal physiology and pathophysiology. Mutations in TRPP1 and TRPP2 have been linked to autosomal dominant polycystic kidney disease (ADPKD), a genetic disorder characterized by the formation of fluid-filled cysts in the kidneys, leading to progressive loss of renal function.
In summary, TRPP cation channels are a subfamily of TRP channels formed by the heterodimerization of TRPP1 and TRPP2 subunits. They play essential roles in sensory perception, cellular signaling, and calcium homeostasis, with particular significance in renal physiology and pathophysiology.
Mitochondrial DNA (mtDNA) is the genetic material present in the mitochondria, which are specialized structures within cells that generate energy. Unlike nuclear DNA, which is present in the cell nucleus and inherited from both parents, mtDNA is inherited solely from the mother.
MtDNA is a circular molecule that contains 37 genes, including 13 genes that encode for proteins involved in oxidative phosphorylation, a process that generates energy in the form of ATP. The remaining genes encode for rRNAs and tRNAs, which are necessary for protein synthesis within the mitochondria.
Mutations in mtDNA can lead to a variety of genetic disorders, including mitochondrial diseases, which can affect any organ system in the body. These mutations can also be used in forensic science to identify individuals and establish biological relationships.
The retina is the innermost, light-sensitive layer of tissue in the eye of many vertebrates and some cephalopods. It receives light that has been focused by the cornea and lens, converts it into neural signals, and sends these to the brain via the optic nerve. The retina contains several types of photoreceptor cells including rods (which handle vision in low light) and cones (which are active in bright light and are capable of color vision).
In medical terms, any pathological changes or diseases affecting the retinal structure and function can lead to visual impairment or blindness. Examples include age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinitis pigmentosa among others.
Blindness is a condition of complete or near-complete vision loss. It can be caused by various factors such as eye diseases, injuries, or birth defects. Total blindness means that a person cannot see anything at all, while near-complete blindness refers to having only light perception or the ability to perceive the direction of light, but not able to discern shapes or forms. Legal blindness is a term used to define a certain level of visual impairment that qualifies an individual for government assistance and benefits; it usually means best corrected visual acuity of 20/200 or worse in the better eye, or a visual field no greater than 20 degrees in diameter.
Eye diseases are a range of conditions that affect the eye or visual system, causing damage to vision and, in some cases, leading to blindness. These diseases can be categorized into various types, including:
1. Refractive errors: These include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, which affect the way light is focused on the retina and can usually be corrected with glasses or contact lenses.
2. Cataracts: A clouding of the lens inside the eye that leads to blurry vision, glare, and decreased contrast sensitivity. Cataract surgery is the most common treatment for this condition.
3. Glaucoma: A group of diseases characterized by increased pressure in the eye, leading to damage to the optic nerve and potential blindness if left untreated. Treatment includes medications, laser therapy, or surgery.
4. Age-related macular degeneration (AMD): A progressive condition that affects the central part of the retina called the macula, causing blurry vision and, in advanced stages, loss of central vision. Treatment may include anti-VEGF injections, laser therapy, or nutritional supplements.
5. Diabetic retinopathy: A complication of diabetes that affects the blood vessels in the retina, leading to bleeding, leakage, and potential blindness if left untreated. Treatment includes laser therapy, anti-VEGF injections, or surgery.
6. Retinal detachment: A separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly with surgery.
7. Amblyopia (lazy eye): A condition where one eye does not develop normal vision, often due to a misalignment or refractive error in childhood. Treatment includes correcting the underlying problem and encouraging the use of the weaker eye through patching or other methods.
8. Strabismus (crossed eyes): A misalignment of the eyes that can lead to amblyopia if not treated promptly with surgery, glasses, or other methods.
9. Corneal diseases: Conditions that affect the transparent outer layer of the eye, such as keratoconus, Fuchs' dystrophy, and infectious keratitis, which can lead to vision loss if not treated promptly.
10. Uveitis: Inflammation of the middle layer of the eye, which can cause vision loss if not treated promptly with anti-inflammatory medications or surgery.
Retinitis pigmentosa (RP) is a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina - a light-sensitive tissue located at the back of the eye. The retina converts light into electrical signals which are then sent to the brain and interpreted as visual images.
In RP, the cells that detect light (rods and cones) degenerate more slowly than other cells in the retina, leading to a progressive loss of vision. Symptoms typically begin in childhood with night blindness (difficulty seeing in low light), followed by a gradual narrowing of the visual field (tunnel vision). Over time, this can lead to significant vision loss and even blindness.
The condition is usually inherited and there are several different genes that have been associated with RP. The diagnosis is typically made based on a combination of genetic testing, family history, and clinical examination. Currently, there is no cure for RP, but researchers are actively working to develop new treatments that may help slow or stop the progression of the disease.
Electroretinography (ERG) is a medical test used to evaluate the functioning of the retina, which is the light-sensitive tissue located at the back of the eye. The test measures the electrical responses of the retina to light stimulation.
During the procedure, a special contact lens or electrode is placed on the surface of the eye to record the electrical activity generated by the retina's light-sensitive cells (rods and cones) and other cells in the retina. The test typically involves presenting different levels of flashes of light to the eye while the electrical responses are recorded.
The resulting ERG waveform provides information about the overall health and function of the retina, including the condition of the photoreceptors, the integrity of the inner retinal layers, and the health of the retinal ganglion cells. This test is often used to diagnose and monitor various retinal disorders, such as retinitis pigmentosa, macular degeneration, and diabetic retinopathy.
Genetic heterogeneity is a phenomenon in genetics where different genetic variations or mutations in various genes can result in the same or similar phenotypic characteristics, disorders, or diseases. This means that multiple genetic alterations can lead to the same clinical presentation, making it challenging to identify the specific genetic cause based on the observed symptoms alone.
There are two main types of genetic heterogeneity:
1. Allelic heterogeneity: Different mutations in the same gene can cause the same or similar disorders. For example, various mutations in the CFTR gene can lead to cystic fibrosis, a genetic disorder affecting the respiratory and digestive systems.
2. Locus heterogeneity: Mutations in different genes can result in the same or similar disorders. For instance, mutations in several genes, such as BRCA1, BRCA2, and PALB2, are associated with an increased risk of developing breast cancer.
Genetic heterogeneity is essential to consider when diagnosing genetic conditions, evaluating recurrence risks, and providing genetic counseling. It highlights the importance of comprehensive genetic testing and interpretation for accurate diagnosis and appropriate management of genetic disorders.
Chromosome mapping, also known as physical mapping, is the process of determining the location and order of specific genes or genetic markers on a chromosome. This is typically done by using various laboratory techniques to identify landmarks along the chromosome, such as restriction enzyme cutting sites or patterns of DNA sequence repeats. The resulting map provides important information about the organization and structure of the genome, and can be used for a variety of purposes, including identifying the location of genes associated with genetic diseases, studying evolutionary relationships between organisms, and developing genetic markers for use in breeding or forensic applications.
A cataract is a clouding of the natural lens in the eye that affects vision. This clouding can cause vision to become blurry, faded, or dim, making it difficult to see clearly. Cataracts are a common age-related condition, but they can also be caused by injury, disease, or medication use. In most cases, cataracts develop gradually over time and can be treated with surgery to remove the cloudy lens and replace it with an artificial one.
Onchocerciasis, Ocular is a medical condition that specifically refers to the eye manifestations caused by the parasitic infection, Onchocerca volvulus. Also known as "river blindness," this disease is spread through the bite of infected blackflies.
Ocular onchocerciasis affects various parts of the eye, including the conjunctiva, cornea, iris, and retina. The infection can cause symptoms such as itching, burning, and redness of the eyes. Over time, it may lead to more serious complications like punctate keratitis (small, scattered opacities on the cornea), cataracts, glaucoma, and ultimately, blindness.
The infection is diagnosed through a skin snip or blood test, which can detect the presence of microfilariae (the larval stage of the parasite) or antibodies against the parasite. Treatment typically involves administering oral medications such as ivermectin, which kills the microfilariae and reduces the risk of eye damage. However, it does not kill the adult worms, so multiple doses are often required to control the infection. In some cases, surgery may be necessary to remove advanced ocular lesions.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.
A nonsense codon is a sequence of three nucleotides in DNA or RNA that does not code for an amino acid. Instead, it signals the end of the protein-coding region of a gene and triggers the termination of translation, the process by which the genetic code is translated into a protein.
In DNA, the nonsense codons are UAA, UAG, and UGA, which are also known as "stop codons." When these codons are encountered during translation, they cause the release of the newly synthesized polypeptide chain from the ribosome, bringing the process of protein synthesis to a halt.
Nonsense mutations are changes in the DNA sequence that result in the appearance of a nonsense codon where an amino acid-coding codon used to be. These types of mutations can lead to premature termination of translation and the production of truncated, nonfunctional proteins, which can cause genetic diseases or contribute to cancer development.
Diabetes Insipidus is a medical condition characterized by the excretion of large amounts of dilute urine (polyuria) and increased thirst (polydipsia). It is caused by a deficiency in the hormone vasopressin (also known as antidiuretic hormone or ADH), which regulates the body's water balance.
In normal physiology, vasopressin is released from the posterior pituitary gland in response to an increase in osmolality of the blood or a decrease in blood volume. This causes the kidneys to retain water and concentrate the urine. In Diabetes Insipidus, there is either a lack of vasopressin production (central diabetes insipidus) or a decreased response to vasopressin by the kidneys (nephrogenic diabetes insipidus).
Central Diabetes Insipidus can be caused by damage to the hypothalamus or pituitary gland, such as from tumors, trauma, or surgery. Nephrogenic Diabetes Insipidus can be caused by genetic factors, kidney disease, or certain medications that interfere with the action of vasopressin on the kidneys.
Treatment for Diabetes Insipidus depends on the underlying cause. In central diabetes insipidus, desmopressin, a synthetic analogue of vasopressin, can be administered to replace the missing hormone. In nephrogenic diabetes insipidus, treatment may involve addressing the underlying kidney disease or adjusting medications that interfere with vasopressin action. It is important for individuals with Diabetes Insipidus to maintain adequate hydration and monitor their fluid intake and urine output.
The optic lobe in non-mammals refers to a specific region of the brain that is responsible for processing visual information. It is a part of the protocerebrum in the insect brain and is analogous to the mammalian visual cortex. The optic lobes receive input directly from the eyes via the optic nerves and are involved in the interpretation and integration of visual stimuli, enabling non-mammals to perceive and respond to their environment. In some invertebrates, like insects, the optic lobe is further divided into subregions, including the lamina, medulla, and lobula, each with distinct functions in visual processing.
Ischemic optic neuropathy (ION) is a medical condition that refers to the damage or death of the optic nerve due to insufficient blood supply. The optic nerve is responsible for transmitting visual information from the eye to the brain.
In ION, the blood vessels that supply the optic nerve become blocked or narrowed, leading to decreased blood flow and oxygen delivery to the nerve fibers. This results in inflammation, swelling, and ultimately, damage to the optic nerve. The damage can cause sudden, painless vision loss, often noticed upon waking up in the morning.
There are two types of ION: anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). AION affects the front part of the optic nerve, while PION affects the back part of the nerve. AION is further classified into arteritic and non-arteritic types, depending on whether it is caused by giant cell arteritis or not.
Risk factors for ION include age (most commonly occurring in people over 50), hypertension, diabetes, smoking, sleep apnea, and other cardiovascular diseases. Treatment options depend on the type and cause of ION and may include controlling underlying medical conditions, administering corticosteroids, or undergoing surgical procedures to improve blood flow.
Multiple System Atrophy (MSA) is a rare, progressive neurodegenerative disorder that affects multiple systems in the body. It is characterized by a combination of symptoms including Parkinsonism (such as stiffness, slowness of movement, and tremors), cerebellar ataxia (lack of muscle coordination), autonomic dysfunction (problems with the autonomic nervous system which controls involuntary actions like heart rate, blood pressure, sweating, and digestion), and pyramidal signs (abnormalities in the corticospinal tracts that control voluntary movements).
The disorder is caused by the degeneration of nerve cells in various parts of the brain and spinal cord, leading to a loss of function in these areas. The exact cause of MSA is unknown, but it is thought to involve a combination of genetic and environmental factors. There is currently no cure for MSA, and treatment is focused on managing symptoms and improving quality of life.
Glutarates are compounds that contain a glutaric acid group. Glutaric acid is a carboxylic acid with a five-carbon chain and two carboxyl groups at the 1st and 5th carbon positions. Glutarates can be found in various substances, including certain foods and medications.
In a medical context, glutarates are sometimes used as ingredients in pharmaceutical products. For example, sodium phenylbutyrate, which is a salt of phenylbutyric acid and butyric acid, contains a glutaric acid group and is used as a medication to treat urea cycle disorders.
Glutarates can also be found in some metabolic pathways in the body, where they play a role in energy production and other biochemical processes. However, abnormal accumulation of glutaric acid or its derivatives can lead to certain medical conditions, such as glutaric acidemia type I, which is an inherited disorder of metabolism that can cause neurological symptoms and other health problems.
Optic flow is not a medical term per se, but rather a term used in the field of visual perception and neuroscience. It refers to the pattern of motion of objects in the visual field that occurs as an observer moves through the environment. This pattern of motion is important for the perception of self-motion and the estimation of egocentric distance (the distance of objects in the environment relative to the observer). Optic flow has been studied in relation to various clinical populations, such as individuals with vestibular disorders or visual impairments, who may have difficulty processing optic flow information.
"Fundus Oculi" is a medical term that refers to the back part of the interior of the eye, including the optic disc, macula, fovea, retinal vasculature, and peripheral retina. It is the area where light is focused and then transmitted to the brain via the optic nerve, forming visual images. Examinations of the fundus oculi are crucial for detecting various eye conditions such as diabetic retinopathy, macular degeneration, glaucoma, and other retinal diseases. The examination is typically performed using an ophthalmoscope or a specialized camera called a retinal camera.
Sensorineural hearing loss (SNHL) is a type of hearing impairment that occurs due to damage to the inner ear (cochlea) or to the nerve pathways from the inner ear to the brain. It can be caused by various factors such as aging, exposure to loud noises, genetics, certain medical conditions (like diabetes and heart disease), and ototoxic medications.
SNHL affects the ability of the hair cells in the cochlea to convert sound waves into electrical signals that are sent to the brain via the auditory nerve. As a result, sounds may be perceived as muffled, faint, or distorted, making it difficult to understand speech, especially in noisy environments.
SNHL is typically permanent and cannot be corrected with medication or surgery, but hearing aids or cochlear implants can help improve communication and quality of life for those affected.
A haplotype is a group of genes or DNA sequences that are inherited together from a single parent. It refers to a combination of alleles (variant forms of a gene) that are located on the same chromosome and are usually transmitted as a unit. Haplotypes can be useful in tracing genetic ancestry, understanding the genetic basis of diseases, and developing personalized medical treatments.
In population genetics, haplotypes are often used to study patterns of genetic variation within and between populations. By comparing haplotype frequencies across populations, researchers can infer historical events such as migrations, population expansions, and bottlenecks. Additionally, haplotypes can provide information about the evolutionary history of genes and genomic regions.
In clinical genetics, haplotypes can be used to identify genetic risk factors for diseases or to predict an individual's response to certain medications. For example, specific haplotypes in the HLA gene region have been associated with increased susceptibility to certain autoimmune diseases, while other haplotypes in the CYP450 gene family can affect how individuals metabolize drugs.
Overall, haplotypes provide a powerful tool for understanding the genetic basis of complex traits and diseases, as well as for developing personalized medical treatments based on an individual's genetic makeup.
Mitochondrial diseases are a group of disorders caused by dysfunctions in the mitochondria, which are the energy-producing structures in cells. These diseases can affect people of any age and can manifest in various ways, depending on which organs or systems are affected. Common symptoms include muscle weakness, neurological problems, cardiac disease, diabetes, and vision/hearing loss. Mitochondrial diseases can be inherited from either the mother's or father's side, or they can occur spontaneously due to genetic mutations. They can range from mild to severe and can even be life-threatening in some cases.
'Abnormalities, Multiple' is a broad term that refers to the presence of two or more structural or functional anomalies in an individual. These abnormalities can be present at birth (congenital) or can develop later in life (acquired). They can affect various organs and systems of the body and can vary greatly in severity and impact on a person's health and well-being.
Multiple abnormalities can occur due to genetic factors, environmental influences, or a combination of both. Chromosomal abnormalities, gene mutations, exposure to teratogens (substances that cause birth defects), and maternal infections during pregnancy are some of the common causes of multiple congenital abnormalities.
Examples of multiple congenital abnormalities include Down syndrome, Turner syndrome, and VATER/VACTERL association. Acquired multiple abnormalities can result from conditions such as trauma, infection, degenerative diseases, or cancer.
The medical evaluation and management of individuals with multiple abnormalities depend on the specific abnormalities present and their impact on the individual's health and functioning. A multidisciplinary team of healthcare professionals is often involved in the care of these individuals to address their complex needs.
Mitochondrial proteins are any proteins that are encoded by the nuclear genome or mitochondrial genome and are located within the mitochondria, an organelle found in eukaryotic cells. These proteins play crucial roles in various cellular processes including energy production, metabolism of lipids, amino acids, and steroids, regulation of calcium homeostasis, and programmed cell death or apoptosis.
Mitochondrial proteins can be classified into two main categories based on their origin:
1. Nuclear-encoded mitochondrial proteins (NEMPs): These are proteins that are encoded by genes located in the nucleus, synthesized in the cytoplasm, and then imported into the mitochondria through specific import pathways. NEMPs make up about 99% of all mitochondrial proteins and are involved in various functions such as oxidative phosphorylation, tricarboxylic acid (TCA) cycle, fatty acid oxidation, and mitochondrial dynamics.
2. Mitochondrial DNA-encoded proteins (MEPs): These are proteins that are encoded by the mitochondrial genome, synthesized within the mitochondria, and play essential roles in the electron transport chain (ETC), a key component of oxidative phosphorylation. The human mitochondrial genome encodes only 13 proteins, all of which are subunits of complexes I, III, IV, and V of the ETC.
Defects in mitochondrial proteins can lead to various mitochondrial disorders, which often manifest as neurological, muscular, or metabolic symptoms due to impaired energy production. These disorders are usually caused by mutations in either nuclear or mitochondrial genes that encode mitochondrial proteins.
Visual fields refer to the total area in which objects can be seen while keeping the eyes focused on a central point. It is the entire area that can be observed using peripheral (side) vision while the eye gazes at a fixed point. A visual field test is used to detect blind spots or gaps (scotomas) in a person's vision, which could indicate various medical conditions such as glaucoma, retinal damage, optic nerve disease, brain tumors, or strokes. The test measures both the central and peripheral vision and maps the entire area that can be seen when focusing on a single point.
"Family Health" is not a term that has a single, widely accepted medical definition. However, in the context of healthcare and public health, "family health" often refers to the physical, mental, and social well-being of all members of a family unit. It includes the assessment, promotion, and prevention of health conditions that affect individual family members as well as the family as a whole.
Family health may also encompass interventions and programs that aim to strengthen family relationships, communication, and functioning, as these factors can have a significant impact on overall health outcomes. Additionally, family health may involve addressing social determinants of health, such as poverty, housing, and access to healthcare, which can affect the health of families and communities.
Overall, family health is a holistic approach to healthcare that recognizes the importance of considering the needs and experiences of all family members in promoting and maintaining good health.
Medical Definition:
Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.
Color vision defects, also known as color blindness, are conditions in which a person has difficulty distinguishing between certain colors. The most common types of color vision defects involve the inability to distinguish between red and green or blue and yellow. These deficiencies result from an alteration or absence of one or more of the three types of cone cells in the retina that are responsible for normal color vision.
In red-green color vision defects, there is a problem with either the red or green cones, or both. This results in difficulty distinguishing between these two colors and their shades. Protanopia is a type of red-green color vision defect where there is an absence of red cone cells, making it difficult to distinguish between red and green as well as between red and black or green and black. Deuteranopia is another type of red-green color vision defect where there is an absence of green cone cells, resulting in similar difficulties distinguishing between red and green, as well as between blue and yellow.
Blue-yellow color vision defects are less common than red-green color vision defects. Tritanopia is a type of blue-yellow color vision defect where there is an absence of blue cone cells, making it difficult to distinguish between blue and yellow, as well as between blue and purple or yellow and pink.
Color vision defects are usually inherited and present from birth, but they can also result from eye diseases, chemical exposure, aging, or medication side effects. They affect both men and women, although red-green color vision defects are more common in men than in women. People with color vision defects may have difficulty with tasks that require color discrimination, such as matching clothes, selecting ripe fruit, reading colored maps, or identifying warning signals. However, most people with mild to moderate color vision defects can adapt and function well in daily life.
Deafness is a hearing loss that is so severe that it results in significant difficulty in understanding or comprehending speech, even when using hearing aids. It can be congenital (present at birth) or acquired later in life due to various causes such as disease, injury, infection, exposure to loud noises, or aging. Deafness can range from mild to profound and may affect one ear (unilateral) or both ears (bilateral). In some cases, deafness may be accompanied by tinnitus, which is the perception of ringing or other sounds in the ears.
Deaf individuals often use American Sign Language (ASL) or other forms of sign language to communicate. Some people with less severe hearing loss may benefit from hearing aids, cochlear implants, or other assistive listening devices. Deafness can have significant social, educational, and vocational implications, and early intervention and appropriate support services are critical for optimal development and outcomes.
Mitochondrial dynamics refer to the processes that regulate the shape, size, distribution, and quality control of mitochondria within cells. These dynamic processes include:
1. Mitochondrial Fusion: This is the process by which two adjacent mitochondria merge together to form a single, elongated organelle. Fusion allows for the exchange of mitochondrial content, including DNA, proteins, and metabolites, which helps maintain genetic stability and promote bioenergetic efficiency.
2. Mitochondrial Fission: This is the process by which a single mitochondrion divides into two separate organelles. Fission plays a crucial role in mitochondrial division, inheritance, and quality control, as it enables the segregation of damaged or dysfunctional mitochondria for degradation via autophagy (mitophagy).
3. Mitochondrial Transport: This is the active movement of mitochondria within cells, facilitated by cytoskeletal motor proteins. Mitochondrial transport enables organelles to be distributed evenly throughout the cell and to reach specific subcellular locations where their energy demands are high.
4. Mitochondrial Dynamics Regulation: The regulation of mitochondrial dynamics involves a complex interplay between various proteins, lipids, and signaling pathways that control fusion, fission, transport, and quality control processes. These regulatory mechanisms help maintain the balance between mitochondrial biogenesis (the generation of new organelles) and mitophagy (the removal of damaged ones), ensuring proper cellular homeostasis and function.
Dysregulation of mitochondrial dynamics has been implicated in various pathological conditions, including neurodegenerative diseases, metabolic disorders, and aging-related processes.
Myoclonic cerebellar dyssynergia is not a widely recognized or formally defined medical term. However, based on its individual components, it can be inferred to refer to a neurological condition characterized by:
1. Myoclonus: These are sudden, involuntary jerking movements of a muscle or group of muscles. They typically occur as a result of hyperexcitability of the neurons in the brain that control movement (motor neurons).
2. Cerebellar: The cerebellum is a part of the brain responsible for coordinating muscle movements, maintaining posture and balance, and fine-tuning motor skills. When a condition is described as "cerebellar," it implies that there is some dysfunction or abnormality in this region of the brain.
3. Dyssynergia: This term refers to a lack of coordination between muscles and muscle groups during voluntary movements. It can result from damage to the cerebellum or other parts of the nervous system involved in motor control.
Therefore, myoclonic cerebellar dyssynergia could be interpreted as a condition characterized by involuntary muscle jerks (myoclonus) and impaired coordination of voluntary movements (dyssynergia), likely due to cerebellar dysfunction. However, it is essential to consult with a medical professional for an accurate diagnosis and treatment plan if you or someone else experiences symptoms that may align with this description.
Low vision is a term used to describe significant visual impairment that cannot be corrected with standard glasses, contact lenses, medication or surgery. It is typically defined as visual acuity of less than 20/70 in the better-seeing eye after best correction, or a visual field of less than 20 degrees in the better-seeing eye.
People with low vision may have difficulty performing everyday tasks such as reading, recognizing faces, watching television, driving, or simply navigating their environment. They may also experience symptoms such as sensitivity to light, glare, or contrast, and may benefit from the use of visual aids, assistive devices, and rehabilitation services to help them maximize their remaining vision and maintain their independence.
Low vision can result from a variety of causes, including eye diseases such as macular degeneration, diabetic retinopathy, glaucoma, or cataracts, as well as congenital or inherited conditions, brain injuries, or aging. It is important for individuals with low vision to receive regular eye examinations and consult with a low vision specialist to determine the best course of treatment and management.
A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.
Microcephaly is a medical condition where an individual has a smaller than average head size. The circumference of the head is significantly below the normal range for age and sex. This condition is typically caused by abnormal brain development, which can be due to genetic factors or environmental influences such as infections or exposure to harmful substances during pregnancy.
Microcephaly can be present at birth (congenital) or develop in the first few years of life. People with microcephaly often have intellectual disabilities, delayed development, and other neurological problems. However, the severity of these issues can vary widely, ranging from mild to severe. It is important to note that not all individuals with microcephaly will experience significant impairments or challenges.
Consanguinity is a medical and genetic term that refers to the degree of genetic relationship between two individuals who share common ancestors. Consanguineous relationships exist when people are related by blood, through a common ancestor or siblings who have children together. The closer the relationship between the two individuals, the higher the degree of consanguinity.
The degree of consanguinity is typically expressed as a percentage or fraction, with higher values indicating a closer genetic relationship. For example, first-degree relatives, such as parents and children or full siblings, share approximately 50% of their genes and have a consanguinity coefficient of 0.25 (or 25%).
Consanguinity can increase the risk of certain genetic disorders and birth defects in offspring due to the increased likelihood of sharing harmful recessive genes. The risks depend on the degree of consanguinity, with closer relationships carrying higher risks. It is important for individuals who are planning to have children and have a history of consanguinity to consider genetic counseling and testing to assess their risk of passing on genetic disorders.
Spinal muscular atrophies (SMAs) of childhood are a group of inherited neuromuscular disorders characterized by degeneration and loss of lower motor neurons in the spinal cord, leading to progressive muscle weakness and atrophy. The severity and age of onset can vary significantly, with some forms presenting in infancy and others in later childhood or even adulthood.
The most common form of SMA is 5q autosomal recessive SMA, also known as survival motor neuron (SMN) disease, which results from mutations in the SMN1 gene. The severity of this form can range from severe (type I or Werdnig-Hoffmann disease), intermediate (type II or chronic infantile neurodegenerative disorder), to mild (type III or Kugelberg-Welander disease).
Type I SMA is the most severe form, with onset before 6 months of age and rapid progression leading to death within the first two years of life if left untreated. Type II SMA has an onset between 6 and 18 months of age, with affected children never achieving the ability to walk independently. Type III SMA has a later onset, typically after 18 months of age, and is characterized by a slower progression, allowing for the ability to walk unaided, although mobility may be lost over time.
Other forms of childhood-onset SMA include autosomal dominant distal SMA, X-linked SMA, and spinal bulbar muscular atrophy (SBMA or Kennedy's disease). These forms have distinct genetic causes and clinical presentations.
In general, SMAs are characterized by muscle weakness, hypotonia, fasciculations, tongue atrophy, and depressed or absent deep tendon reflexes. Respiratory and nutritional support is often required in more severe cases. Recent advances in gene therapy have led to the development of disease-modifying treatments for some forms of SMA.
I'm sorry for any confusion, but "Optics and Photonics" is a broad field that encompasses various scientific and engineering disciplines. It doesn't have a specific medical definition, as it's not a term typically used in a medical context.
However, I can provide a general definition:
Optics is the study of light and its interactions with matter. This includes how light is produced, controlled, transmitted, and detected. It involves phenomena such as reflection, refraction, diffraction, and interference.
Photonics, on the other hand, is a branch of optics that deals with the generation, detection, and manipulation of individual photons, the basic units of light. Photonics is often applied to technologies such as lasers, fiber optics, and optical communications.
In a medical context, these fields might be used in various diagnostic and therapeutic applications, such as endoscopes, ophthalmic devices, laser surgery, and imaging technologies like MRI and CT scans. But the terms "Optics" and "Photonics" themselves are not medical conditions or treatments.
An Optic Nerve Glioma is a type of brain tumor that arises from the glial cells (supportive tissue) within the optic nerve. It is most commonly seen in children, particularly those with neurofibromatosis type 1 (NF1). These tumors are typically slow-growing and may not cause any symptoms, especially if they are small. However, as they grow larger, they can put pressure on the optic nerve, leading to vision loss or other visual disturbances. In some cases, these tumors can also affect nearby structures in the brain, causing additional neurological symptoms. Treatment options may include observation, chemotherapy, radiation therapy, or surgery, depending on the size and location of the tumor, as well as the patient's age and overall health.
Mitochondria are specialized structures located inside cells that convert the energy from food into ATP (adenosine triphosphate), which is the primary form of energy used by cells. They are often referred to as the "powerhouses" of the cell because they generate most of the cell's supply of chemical energy. Mitochondria are also involved in various other cellular processes, such as signaling, differentiation, and apoptosis (programmed cell death).
Mitochondria have their own DNA, known as mitochondrial DNA (mtDNA), which is inherited maternally. This means that mtDNA is passed down from the mother to her offspring through the egg cells. Mitochondrial dysfunction has been linked to a variety of diseases and conditions, including neurodegenerative disorders, diabetes, and aging.
Human chromosome pair 3 consists of two rod-shaped structures present in the nucleus of each cell in the human body. Each member of the pair is a single chromosome, and together they contain the genetic material that is inherited from both parents. Chromosomes are made up of DNA, which contains the instructions for the development and function of all living organisms.
Human chromosomes are numbered from 1 to 22, with an additional two sex chromosomes (X and Y) that determine biological sex. Chromosome pair 3 is one of the autosomal pairs, meaning it contains genes that are not related to sex determination. Each member of chromosome pair 3 is identical in size and shape and contains a single long DNA molecule that is coiled tightly around histone proteins to form a compact structure.
Chromosome pair 3 is associated with several genetic disorders, including Waardenburg syndrome, which affects pigmentation and hearing; Marfan syndrome, which affects the connective tissue; and some forms of retinoblastoma, a rare eye cancer that typically affects young children.
Nerve fibers are specialized structures that constitute the long, slender processes (axons) of neurons (nerve cells). They are responsible for conducting electrical impulses, known as action potentials, away from the cell body and transmitting them to other neurons or effector organs such as muscles and glands. Nerve fibers are often surrounded by supportive cells called glial cells and are grouped together to form nerve bundles or nerves. These fibers can be myelinated (covered with a fatty insulating sheath called myelin) or unmyelinated, which influences the speed of impulse transmission.
Genotype, in genetics, refers to the complete heritable genetic makeup of an individual organism, including all of its genes. It is the set of instructions contained in an organism's DNA for the development and function of that organism. The genotype is the basis for an individual's inherited traits, and it can be contrasted with an individual's phenotype, which refers to the observable physical or biochemical characteristics of an organism that result from the expression of its genes in combination with environmental influences.
It is important to note that an individual's genotype is not necessarily identical to their genetic sequence. Some genes have multiple forms called alleles, and an individual may inherit different alleles for a given gene from each parent. The combination of alleles that an individual inherits for a particular gene is known as their genotype for that gene.
Understanding an individual's genotype can provide important information about their susceptibility to certain diseases, their response to drugs and other treatments, and their risk of passing on inherited genetic disorders to their offspring.
Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:
1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction
Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:
1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.
Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).
Evoked potentials, visual, also known as visually evoked potentials (VEPs), are electrical responses recorded from the brain following the presentation of a visual stimulus. These responses are typically measured using electroencephalography (EEG) and can provide information about the functioning of the visual pathways in the brain.
There are several types of VEPs, including pattern-reversal VEPs and flash VEPs. Pattern-reversal VEPs are elicited by presenting alternating checkerboard patterns, while flash VEPs are elicited by flashing a light. The responses are typically analyzed in terms of their latency (the time it takes for the response to occur) and amplitude (the size of the response).
VEPs are often used in clinical settings to help diagnose and monitor conditions that affect the visual system, such as multiple sclerosis, optic neuritis, and brainstem tumors. They can also be used in research to study the neural mechanisms underlying visual perception.
Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.
The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.
Examples of animal disease models include:
1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.
Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.
The Founder Effect is a concept in population genetics that refers to the loss of genetic variation that occurs when a new colony is established by a small number of individuals from a larger population. This decrease in genetic diversity can lead to an increase in homozygosity, which can in turn result in a higher frequency of certain genetic disorders or traits within the founding population and its descendants. The Founder Effect is named after the "founding" members of the new colony who carry and pass on their particular set of genes to the next generations. It is one of the mechanisms that can lead to the formation of distinct populations or even new species over time.
Olivopontocerebellar atrophies (OPCA) are a group of rare, progressive neurodegenerative disorders that primarily affect the cerebellum, olive (inferior olivary nucleus), and pons in the brainstem. The condition is characterized by degeneration and atrophy of these specific areas, leading to various neurological symptoms.
The term "olivopontocerebellar atrophies" encompasses several subtypes, including:
1. Hereditary spastic paraplegia with cerebellar ataxia (SPG/ATA) - Autosomal dominant or recessive inheritance pattern.
2. Hereditary dentatorubral-pallidoluysian atrophy (DRPLA) - Autosomal dominant inheritance pattern.
3. Idiopathic OPCA - No known genetic cause, possibly related to environmental factors or spontaneous mutations.
Symptoms of olivopontocerebellar atrophies may include:
* Progressive cerebellar ataxia (gait and limb incoordination)
* Dysarthria (slurred speech)
* Oculomotor abnormalities (nystagmus, gaze palsy)
* Spasticity (stiffness and rigidity of muscles)
* Dysphagia (difficulty swallowing)
* Tremors or dystonia (involuntary muscle contractions)
Diagnosis typically involves a combination of clinical examination, neuroimaging studies (MRI), genetic testing, and exclusion of other possible causes. Currently, there is no cure for olivopontocerebellar atrophies, but supportive care can help manage symptoms and improve quality of life.
A point mutation is a type of genetic mutation where a single nucleotide base (A, T, C, or G) in DNA is altered, deleted, or substituted with another nucleotide. Point mutations can have various effects on the organism, depending on the location of the mutation and whether it affects the function of any genes. Some point mutations may not have any noticeable effect, while others might lead to changes in the amino acids that make up proteins, potentially causing diseases or altering traits. Point mutations can occur spontaneously due to errors during DNA replication or be inherited from parents.
Spinocerebellar degenerations (SCDs) are a group of genetic disorders that primarily affect the cerebellum, the part of the brain responsible for coordinating muscle movements, and the spinal cord. These conditions are characterized by progressive degeneration or loss of nerve cells in the cerebellum and/or spinal cord, leading to various neurological symptoms.
SCDs are often inherited in an autosomal dominant manner, meaning that only one copy of the altered gene from either parent is enough to cause the disorder. The most common type of SCD is spinocerebellar ataxia (SCA), which includes several subtypes (SCA1, SCA2, SCA3, etc.) differentiated by their genetic causes and specific clinical features.
Symptoms of spinocerebellar degenerations may include:
1. Progressive ataxia (loss of coordination and balance)
2. Dysarthria (speech difficulty)
3. Nystagmus (involuntary eye movements)
4. Oculomotor abnormalities (problems with eye movement control)
5. Tremors or other involuntary muscle movements
6. Muscle weakness and spasticity
7. Sensory disturbances, such as numbness or tingling sensations
8. Dysphagia (difficulty swallowing)
9. Cognitive impairment in some cases
The age of onset, severity, and progression of symptoms can vary significantly among different SCD subtypes and individuals. Currently, there is no cure for spinocerebellar degenerations, but various supportive treatments and therapies can help manage symptoms and improve quality of life.
Polycystic Kidney Disease (PKD) is a genetic disorder characterized by the growth of multiple cysts in the kidneys. These cysts are fluid-filled sacs that can vary in size and can multiply, leading to enlarged kidneys. The increased size and number of cysts can result in reduced kidney function, high blood pressure, and eventually kidney failure.
There are two main types of PKD: Autosomal Dominant Polycystic Kidney Disease (ADPKD) and Autosomal Recessive Polycystic Kidney Disease (ARPKD). ADPKD is the most common form, affecting approximately 1 in every 500 people. It typically develops in adulthood. On the other hand, ARPKD is a rarer form, affecting about 1 in every 20,000 children, and it often presents in infancy or early childhood.
In addition to kidney problems, PKD can also affect other organs, such as the liver and the heart. It's important to note that while there is no cure for PKD, various treatments can help manage symptoms and slow down the progression of the disease.
CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is a genetic disorder that affects the small blood vessels in the brain. It is caused by mutations in the NOTCH3 gene, which leads to the progressive degeneration of these vessels.
The symptoms of CADASIL typically begin in middle age and include migraine with aura, recurrent strokes or transient ischemic attacks (TIAs), cognitive decline, and psychiatric symptoms such as depression and apathy. The condition can also cause physical disabilities such as difficulty walking and urinary incontinence.
CADASIL is an inherited disorder, meaning that it is passed down from parent to child through a mutated gene. If one parent has the disease, each child has a 50% chance of inheriting the mutated gene and developing the condition. Currently, there is no cure for CADASIL, but treatments can help manage symptoms and improve quality of life.
A homozygote is an individual who has inherited the same allele (version of a gene) from both parents and therefore possesses two identical copies of that allele at a specific genetic locus. This can result in either having two dominant alleles (homozygous dominant) or two recessive alleles (homozygous recessive). In contrast, a heterozygote has inherited different alleles from each parent for a particular gene.
The term "homozygote" is used in genetics to describe the genetic makeup of an individual at a specific locus on their chromosomes. Homozygosity can play a significant role in determining an individual's phenotype (observable traits), as having two identical alleles can strengthen the expression of certain characteristics compared to having just one dominant and one recessive allele.
Retinal diseases refer to a group of conditions that affect the retina, which is the light-sensitive tissue located at the back of the eye. The retina is responsible for converting light into electrical signals that are sent to the brain and interpreted as visual images. Retinal diseases can cause vision loss or even blindness, depending on their severity and location in the retina.
Some common retinal diseases include:
1. Age-related macular degeneration (AMD): A progressive disease that affects the central part of the retina called the macula, causing blurred or distorted vision.
2. Diabetic retinopathy: A complication of diabetes that can damage the blood vessels in the retina, leading to vision loss.
3. Retinal detachment: A serious condition where the retina becomes separated from its underlying tissue, requiring immediate medical attention.
4. Macular edema: Swelling or thickening of the macula due to fluid accumulation, which can cause blurred vision.
5. Retinitis pigmentosa: A group of inherited eye disorders that affect the retina's ability to respond to light, causing progressive vision loss.
6. Macular hole: A small break in the macula that can cause distorted or blurry vision.
7. Retinal vein occlusion: Blockage of the retinal veins that can lead to bleeding, swelling, and potential vision loss.
Treatment for retinal diseases varies depending on the specific condition and its severity. Some treatments include medication, laser therapy, surgery, or a combination of these options. Regular eye exams are essential for early detection and treatment of retinal diseases.
Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance of developing or passing on a genetic disorder. Genetic tests are performed on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds a fetus during pregnancy), or other tissue. For example, a physician may recommend genetic testing to help diagnose a genetic condition, confirm the presence of a gene mutation known to increase the risk of developing certain cancers, or determine the chance for a couple to have a child with a genetic disorder.
There are several types of genetic tests, including:
* Diagnostic testing: This type of test is used to identify or confirm a suspected genetic condition in an individual. It may be performed before birth (prenatal testing) or at any time during a person's life.
* Predictive testing: This type of test is used to determine the likelihood that a person will develop a genetic disorder. It is typically offered to individuals who have a family history of a genetic condition but do not show any symptoms themselves.
* Carrier testing: This type of test is used to determine whether a person carries a gene mutation for a genetic disorder. It is often offered to couples who are planning to have children and have a family history of a genetic condition or belong to a population that has an increased risk of certain genetic disorders.
* Preimplantation genetic testing: This type of test is used in conjunction with in vitro fertilization (IVF) to identify genetic changes in embryos before they are implanted in the uterus. It can help couples who have a family history of a genetic disorder or who are at risk of having a child with a genetic condition to conceive a child who is free of the genetic change in question.
* Pharmacogenetic testing: This type of test is used to determine how an individual's genes may affect their response to certain medications. It can help healthcare providers choose the most effective medication and dosage for a patient, reducing the risk of adverse drug reactions.
It is important to note that genetic testing should be performed under the guidance of a qualified healthcare professional who can interpret the results and provide appropriate counseling and support.
A heterozygote is an individual who has inherited two different alleles (versions) of a particular gene, one from each parent. This means that the individual's genotype for that gene contains both a dominant and a recessive allele. The dominant allele will be expressed phenotypically (outwardly visible), while the recessive allele may or may not have any effect on the individual's observable traits, depending on the specific gene and its function. Heterozygotes are often represented as 'Aa', where 'A' is the dominant allele and 'a' is the recessive allele.
A visual field test is a method used to measure an individual's entire scope of vision, which includes what can be seen straight ahead and in peripheral (or side) vision. During the test, the person being tested is asked to focus on a central point while gradually identifying the appearance of objects moving into their peripheral vision. The visual field test helps detect blind spots (scotomas) or gaps in the visual field, which can be caused by various conditions such as glaucoma, brain injury, optic nerve damage, or retinal disorders. It's an essential tool for diagnosing and monitoring eye-related diseases and conditions.
Optic nerve diseases refer to a group of conditions that affect the optic nerve, which transmits visual information from the eye to the brain. These diseases can cause various symptoms such as vision loss, decreased visual acuity, changes in color vision, and visual field defects. Examples of optic nerve diseases include optic neuritis (inflammation of the optic nerve), glaucoma (damage to the optic nerve due to high eye pressure), optic nerve damage from trauma or injury, ischemic optic neuropathy (lack of blood flow to the optic nerve), and optic nerve tumors. Treatment for optic nerve diseases varies depending on the specific condition and may include medications, surgery, or lifestyle changes.
Penetrance, in medical genetics, refers to the proportion of individuals with a particular genetic variant or mutation who exhibit clinical features or symptoms of a resulting disease. It is often expressed as a percentage, with complete penetrance indicating that all individuals with the genetic change will develop the disease, and reduced or incomplete penetrance suggesting that not all individuals with the genetic change will necessarily develop the disease, even if they express some of its characteristics.
Penetrance can vary depending on various factors such as age, sex, environmental influences, and interactions with other genes. Incomplete penetrance is common in many genetic disorders, making it challenging to predict who will develop symptoms based solely on their genotype.
NADH dehydrogenase, also known as Complex I, is an enzyme complex in the electron transport chain located in the inner mitochondrial membrane. It catalyzes the oxidation of NADH to NAD+ and the reduction of coenzyme Q to ubiquinol, playing a crucial role in cellular respiration and energy production. The reaction involves the transfer of electrons from NADH to coenzyme Q, which contributes to the generation of a proton gradient across the membrane, ultimately leading to ATP synthesis. Defects in NADH dehydrogenase can result in various mitochondrial diseases and disorders.
The "age of onset" is a medical term that refers to the age at which an individual first develops or displays symptoms of a particular disease, disorder, or condition. It can be used to describe various medical conditions, including both physical and mental health disorders. The age of onset can have implications for prognosis, treatment approaches, and potential causes of the condition. In some cases, early onset may indicate a more severe or progressive course of the disease, while late-onset symptoms might be associated with different underlying factors or etiologies. It is essential to provide accurate and precise information regarding the age of onset when discussing a patient's medical history and treatment plan.
Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.
The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.
In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.
Eye proteins, also known as ocular proteins, are specific proteins that are found within the eye and play crucial roles in maintaining proper eye function and health. These proteins can be found in various parts of the eye, including the cornea, iris, lens, retina, and other structures. They perform a wide range of functions, such as:
1. Structural support: Proteins like collagen and elastin provide strength and flexibility to the eye's tissues, enabling them to maintain their shape and withstand mechanical stress.
2. Light absorption and transmission: Proteins like opsins and crystallins are involved in capturing and transmitting light signals within the eye, which is essential for vision.
3. Protection against damage: Some eye proteins, such as antioxidant enzymes and heat shock proteins, help protect the eye from oxidative stress, UV radiation, and other environmental factors that can cause damage.
4. Regulation of eye growth and development: Various growth factors and signaling molecules, which are protein-based, contribute to the proper growth, differentiation, and maintenance of eye tissues during embryonic development and throughout adulthood.
5. Immune defense: Proteins involved in the immune response, such as complement components and immunoglobulins, help protect the eye from infection and inflammation.
6. Maintenance of transparency: Crystallin proteins in the lens maintain its transparency, allowing light to pass through unobstructed for clear vision.
7. Neuroprotection: Certain eye proteins, like brain-derived neurotrophic factor (BDNF), support the survival and function of neurons within the retina, helping to preserve vision.
Dysfunction or damage to these eye proteins can contribute to various eye disorders and diseases, such as cataracts, age-related macular degeneration, glaucoma, diabetic retinopathy, and others.
Intellectual disability (ID) is a term used when there are significant limitations in both intellectual functioning and adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18.
Intellectual functioning, also known as intelligence, refers to general mental capacity, such as learning, reasoning, problem-solving, and other cognitive skills. Adaptive behavior includes skills needed for day-to-day life, such as communication, self-care, social skills, safety judgement, and basic academic skills.
Intellectual disability is characterized by below-average intelligence or mental ability and a lack of skills necessary for day-to-day living. It can be mild, moderate, severe, or profound, depending on the degree of limitation in intellectual functioning and adaptive behavior.
It's important to note that people with intellectual disabilities have unique strengths and limitations, just like everyone else. With appropriate support and education, they can lead fulfilling lives and contribute to their communities in many ways.
Leigh Disease, also known as Subacute Necrotizing Encephalomyelopathy (SNE), is a rare inherited neurometabolic disorder that affects the central nervous system. It is characterized by progressive degeneration of the brain and spinal cord. The condition typically appears in infancy or early childhood, although it can develop in adolescence or adulthood.
Leigh Disease is caused by mutations in mitochondrial DNA or nuclear genes that disrupt the function of the oxidative phosphorylation system, a part of the cellular energy production process. This results in decreased ATP (adenosine triphosphate) production and an accumulation of lactic acid in the body.
The symptoms of Leigh Disease can vary widely but often include vomiting, seizures, developmental delays, muscle weakness, loss of muscle tone, and difficulty swallowing and breathing. The condition can also cause lesions to form on the brainstem and basal ganglia, which can lead to further neurological problems.
There is no cure for Leigh Disease, and treatment is focused on managing symptoms and supporting affected individuals as they cope with the progression of the disease.
Genetic markers are specific segments of DNA that are used in genetic mapping and genotyping to identify specific genetic locations, diseases, or traits. They can be composed of short tandem repeats (STRs), single nucleotide polymorphisms (SNPs), restriction fragment length polymorphisms (RFLPs), or variable number tandem repeats (VNTRs). These markers are useful in various fields such as genetic research, medical diagnostics, forensic science, and breeding programs. They can help to track inheritance patterns, identify genetic predispositions to diseases, and solve crimes by linking biological evidence to suspects or victims.
Gyrate atrophy is a rare inherited eye disorder that is characterized by progressive degeneration of the retina, which is the light-sensitive tissue at the back of the eye. It is caused by a deficiency in an enzyme called ornithine aminotransferase (OAT), which is necessary for the normal metabolism of an amino acid called ornithine.
The accumulation of ornithine in the retinal cells leads to their degeneration and the formation of well-demarcated, circular areas of atrophy (gyrates) in the retina. This can result in decreased vision, night blindness, and a progressive loss of visual field, which can ultimately lead to legal or complete blindness.
Gyrate atrophy is typically inherited as an autosomal recessive trait, meaning that an individual must inherit two copies of the mutated gene (one from each parent) in order to develop the condition. The disorder usually becomes apparent in childhood or adolescence and can progress slowly over several decades. There is currently no cure for gyrate atrophy, but dietary restrictions and supplements may help slow its progression.
Exons are the coding regions of DNA that remain in the mature, processed mRNA after the removal of non-coding intronic sequences during RNA splicing. These exons contain the information necessary to encode proteins, as they specify the sequence of amino acids within a polypeptide chain. The arrangement and order of exons can vary between different genes and even between different versions of the same gene (alternative splicing), allowing for the generation of multiple protein isoforms from a single gene. This complexity in exon structure and usage significantly contributes to the diversity and functionality of the proteome.
An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.
Neurodegenerative diseases are a group of disorders characterized by progressive and persistent loss of neuronal structure and function, often leading to cognitive decline, functional impairment, and ultimately death. These conditions are associated with the accumulation of abnormal protein aggregates, mitochondrial dysfunction, oxidative stress, chronic inflammation, and genetic mutations in the brain. Examples of neurodegenerative diseases include Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis (ALS), and Spinal Muscular Atrophy (SMA). The underlying causes and mechanisms of these diseases are not fully understood, and there is currently no cure for most neurodegenerative disorders. Treatment typically focuses on managing symptoms and slowing disease progression.
Multi-infarct dementia (MID) is a specific type of dementia that is caused by multiple small strokes or mini-strokes (known as transient ischemic attacks or TIAs) in the brain. Also known as vascular dementia, multi-infarct dementia results from the interruption of blood flow to parts of the brain, leading to damage and death of brain tissue.
The term 'multi-infarct' refers to multiple areas (or infarcts) of damaged or dead tissue in the brain due to the lack of oxygen and nutrients caused by these small strokes. Over time, as more areas of the brain are affected, cognitive decline becomes apparent, leading to symptoms such as memory loss, difficulty with problem-solving, disorientation, language problems, and changes in mood or behavior.
Multi-infarct dementia is typically a progressive condition, meaning that symptoms worsen over time. However, the rate of progression can vary depending on factors such as the number and severity of strokes, underlying medical conditions, and lifestyle factors. It's important to note that multi-infarct dementia can be prevented or delayed by controlling risk factors for stroke, such as high blood pressure, diabetes, smoking, and high cholesterol.
Hereditary Spastic Paraplegia (HSP) is a group of genetic disorders that affect the long motor neurons in the spinal cord, leading to lower limb spasticity and weakness. It is characterized by progressive stiffness and contraction of the leg muscles, resulting in difficulty with walking and balance.
The symptoms of HSP typically begin in childhood or early adulthood and worsen over time. The severity of the condition can vary widely, even within the same family, depending on the specific genetic mutation involved. In addition to lower limb spasticity, some individuals with HSP may also experience bladder dysfunction, sensory loss, or other neurological symptoms.
HSP is inherited in an autosomal dominant or autosomal recessive pattern, depending on the specific genetic mutation involved. There are over 70 different genes that have been identified as causing HSP, and genetic testing can be used to confirm the diagnosis and identify the specific genetic mutation responsible.
Treatment for HSP is focused on managing symptoms and maintaining mobility. Physical therapy, orthotics, and medications such as baclofen or tizanidine may be used to help reduce muscle spasticity and improve mobility. In some cases, surgery may be necessary to relieve muscle contractures or other complications.
Human chromosome pair 2 consists of two rod-shaped structures present in the nucleus of each cell of the human body. Each member of the pair contains thousands of genes and other genetic material, encoded in the form of DNA molecules. Chromosomes are the physical carriers of inheritance, and human cells typically contain 23 pairs of chromosomes for a total of 46 chromosomes.
Chromosome pair 2 is one of the autosomal pairs, meaning that it is not a sex chromosome (X or Y). Each member of chromosome pair 2 is approximately 247 million base pairs in length and contains an estimated 1,000-1,300 genes. These genes play crucial roles in various biological processes, including development, metabolism, and response to environmental stimuli.
Abnormalities in chromosome pair 2 can lead to genetic disorders, such as cat-eye syndrome (CES), which is characterized by iris abnormalities, anal atresia, hearing loss, and intellectual disability. This disorder arises from the presence of an extra copy of a small region on chromosome 2, resulting in partial trisomy of this region. Other genetic conditions associated with chromosome pair 2 include proximal 2q13.3 microdeletion syndrome and Potocki-Lupski syndrome (PTLS).
Geographic atrophy is a medical term used to describe a specific pattern of degeneration of the retinal pigment epithelium (RPE) and the underlying choroidal tissue in the eye. This condition is often associated with age-related macular degeneration (AMD), which is a leading cause of vision loss in older adults.
In geographic atrophy, there are well-defined areas of RPE and choroidal atrophy that appear as pale, irregularly shaped patches in the central part of the retina known as the macula. These patches can grow larger over time and may lead to progressive vision loss. The exact cause of geographic atrophy is not fully understood, but it is thought to be related to oxidative stress, inflammation, and other age-related changes in the eye.
Currently, there are no effective treatments for geographic atrophy, although research is ongoing to find new ways to slow or halt its progression. Regular eye exams and monitoring by an ophthalmologist are important for people with AMD or geographic atrophy to help detect any changes in their vision and manage their condition effectively.
Optical coherence tomography (OCT) is a non-invasive imaging technique that uses low-coherence light to capture high-resolution cross-sectional images of biological tissues, particularly the retina and other ocular structures. OCT works by measuring the echo time delay of light scattered back from different depths within the tissue, creating a detailed map of the tissue's structure. This technique is widely used in ophthalmology to diagnose and monitor various eye conditions such as macular degeneration, diabetic retinopathy, and glaucoma.
A coloboma is a congenital condition that results from incomplete closure of the optic fissure during fetal development. This results in a gap or hole in one or more structures of the eye, such as the iris, retina, choroid, or optic nerve. The size and location of the coloboma can vary widely, and it may affect one or both eyes.
Colobomas can cause a range of visual symptoms, depending on their size and location. Some people with colobomas may have no visual impairment, while others may experience reduced vision, double vision, or sensitivity to light. In severe cases, colobomas can lead to blindness.
Colobomas are usually diagnosed during routine eye exams and are typically not treatable, although some visual symptoms may be managed with glasses, contact lenses, or surgery in certain cases. Colobomas can occur as an isolated condition or as part of a genetic syndrome, so individuals with colobomas may benefit from genetic counseling to understand their risk of passing the condition on to their offspring.
A frameshift mutation is a type of genetic mutation that occurs when the addition or deletion of nucleotides in a DNA sequence is not divisible by three. Since DNA is read in groups of three nucleotides (codons), which each specify an amino acid, this can shift the "reading frame," leading to the insertion or deletion of one or more amino acids in the resulting protein. This can cause a protein to be significantly different from the normal protein, often resulting in a nonfunctional protein and potentially causing disease. Frameshift mutations are typically caused by insertions or deletions of nucleotides, but they can also result from more complex genetic rearrangements.
The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:
1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.
The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.
Gene deletion is a type of mutation where a segment of DNA, containing one or more genes, is permanently lost or removed from a chromosome. This can occur due to various genetic mechanisms such as homologous recombination, non-homologous end joining, or other types of genomic rearrangements.
The deletion of a gene can have varying effects on the organism, depending on the function of the deleted gene and its importance for normal physiological processes. If the deleted gene is essential for survival, the deletion may result in embryonic lethality or developmental abnormalities. However, if the gene is non-essential or has redundant functions, the deletion may not have any noticeable effects on the organism's phenotype.
Gene deletions can also be used as a tool in genetic research to study the function of specific genes and their role in various biological processes. For example, researchers may use gene deletion techniques to create genetically modified animal models to investigate the impact of gene deletion on disease progression or development.
Congenital hand deformities refer to physical abnormalities or malformations of the hand, wrist, and/or digits (fingers) that are present at birth. These deformities can result from genetic factors, environmental influences during pregnancy, or a combination of both. They may affect the bones, muscles, tendons, joints, and other structures in the hand, leading to varying degrees of impairment in function and appearance.
There are numerous types of congenital hand deformities, some of which include:
1. Polydactyly: The presence of extra digits on the hand, which can be fully formed or rudimentary.
2. Syndactyly: Webbing or fusion of two or more fingers, which may involve soft tissue only or bone as well.
3. Clinodactyly: A curved finger due to a sideways deviation of the fingertip, often affecting the little finger.
4. Camptodactyly: Permanent flexion or bending of one or more fingers, typically involving the proximal interphalangeal joint.
5. Trigger Finger/Thumb: A condition where a finger or thumb becomes locked in a bent position due to thickening and narrowing of the tendon sheath.
6. Radial Club Hand (Radial Ray Deficiency): Underdevelopment or absence of the radius bone, resulting in a short, curved forearm and hand deformity.
7. Ulnar Club Hand (Ulnar Ray Deficiency): Underdevelopment or absence of the ulna bone, leading to a short, curved forearm and hand deformity.
8. Cleidocranial Dysplasia: A genetic disorder affecting bone growth, resulting in underdeveloped or absent collarbones, dental abnormalities, and occasionally hand deformities.
9. Apert Syndrome: A rare genetic disorder characterized by the fusion of fingers and toes (syndactyly) and other skeletal abnormalities.
10. Holt-Oram Syndrome: A genetic disorder involving heart defects and upper limb deformities, such as radial ray deficiency or thumb anomalies.
Treatment for hand deformities varies depending on the specific condition and severity. Options may include physical therapy, bracing, splinting, medications, or surgical intervention.
Spinocerebellar ataxias (SCAs) are a group of genetic disorders that affect the cerebellum, which is the part of the brain responsible for coordinating muscle movements. SCAs are characterized by progressive problems with balance, speech, and coordination. They are caused by mutations in various genes that result in the production of abnormal proteins that accumulate in neurons, leading to their degeneration.
There are over 40 different types of SCAs, each caused by a different genetic mutation. Some of the more common types include SCA1, SCA2, SCA3, SCA6, and SCA7. The symptoms and age of onset can vary widely depending on the type of SCA.
In addition to problems with coordination and balance, people with SCAs may also experience muscle weakness, stiffness, tremors, spasticity, and difficulty swallowing or speaking. Some types of SCAs can also cause visual disturbances, hearing loss, and cognitive impairment. Currently, there is no cure for SCAs, but treatments such as physical therapy, speech therapy, and medications can help manage the symptoms.
Dynamin-like 120 kDa protein
Bosch-Boonstra-Schaaf optic atrophy syndrome
OPA3
Costeff syndrome
Nektarios Tavernarakis
Taosheng Huang
Hagemoser-Weinstein-Bresnick syndrome
Autosomal dominant cerebellar ataxia, deafness, and narcolepsy
Cone dystrophy
Wolfram-like syndrome
Optic neuropathy
Alfredo Sadun
Kjer's optic neuropathy
PEHO syndrome
Behr syndrome
CAPOS syndrome
Lamb-Shaffer syndrome
Chromosome 3
List of MeSH codes (C18)
List of MeSH codes (C16)
List of MeSH codes (C11)
WFS1
Antisense therapy
Central diabetes insipidus
Mitochondrial optic neuropathies
Macrocephaly
Mitochondrial membrane protein-associated neurodegeneration
Heart-hand syndromes
List of diseases (O)
List of MeSH codes (C10)
Autosomal dominant optic atrophy and cataract: MedlinePlus Genetics
The natural history of OPA1-related autosomal dominant optic atrophy | British Journal of Ophthalmology
Autosomal dominant optic atrophy - Living with the Disease - Genetic and Rare Diseases Information Center
Autosomal dominant optic atrophy and peripheral neuropathy - Global Genes
Non-image-forming light driven functions are preserved in a mouse model of autosomal dominant optic atrophy. - SCNi
Comparison of Lamina Cribrosa Morphology in Normal Tension Glaucoma and Autosomal-Dominant Optic Atrophy - Optic Nerve Network
Multiethnic involvement in autosomal-dominant optic atrophy in Singapore - (Eye 31, 475 (March 2017)) - The Royal College of...
Dynamin-like 120 kDa protein - Wikipedia
Stoke Therapeutics Reports Third Quarter Financial Results and Provides Business Updates
Validating the RedMIT/GFP-LC3 Mouse Model by Studying Mitophagy in Autosomal Dominant Optic Atrophy Due to the OPA1Q285STOP...
Underlying Medical Conditions Associated with Higher Risk for Severe COVID-19: Information for Healthcare Professionals | CDC
ICGNMD Publications | International Centre for Genomic Medicine in Neuromuscular Diseases - UCL - University College London
Optic Neuritis Clinical Guide | Cleveland Clinic
Stoke Therapeutics Reports First Quarter Financial Results and Provides Business Updates | FinancialContent Business Page
Patricia L. Sager | Marketing & Business Development Director | Williams Mullen
Optic Atrophy: Background, Pathophysiology, Epidemiology
Genetic Tests Offered (all nonprofit) | The John and Marcia Carver Nonprofit Genetic Testing Laboratory
Spastic Paraplegia 11 - GeneReviews® - NCBI Bookshelf
Clinical aspects of hereditary hearing loss | Genetics in Medicine
Claes Möller - Institutionen för hälsovetenskaper - Örebro universitet
Investigation of the association between OPA1 polymorphisms and normal-tension glaucoma in Korea
Mitochondrial Fusion Proteins and Human Diseases - Centro Dino Ferrari
3.5 Million Grant to Study Disease Causing Vision Loss in Children | UC Davis
Cross Talk of Proteostasis and Mitostasis in Cellular Homeodynamics, Ageing, and Disease
Dominant optic atrophy mapped to chromosome 3q region. II. Clinical and epidemiological aspects
MedlinePlus - Search Results for: Cataract 19 multiple types
Olivopontocerebellar Atrophy Treatment & Management: Medical Care, Surgical Care, Consultations
Orphanet: Spondylometaphyseal dysplasia
All Science News | News | Foundation for Research and Technology - Hellas
Hereditary Optic Neuropathies - Eye Disorders - MSD Manual Professional Edition
ADOA14
- Autosomal dominant optic atrophy (ADOA) is a slowly progressive optic neuropathy that has been associated with mutations of the OPA1 gene. (ox.ac.uk)
- C3-Opa1(Q285STOP) mouse model of ADOA displays optic nerve abnormalities, RGC dendropathy and functional visual disruption. (ox.ac.uk)
- A rare form of autosomal dominant optic atrophy (ADOA) characterized by progressive and isolated visual loss in the first decade of life decreased reflexes in the lower limbs and a mild cerebellar stance. (globalgenes.org)
- PURPOSE: To compare lamina cribrosa (LC) morphology in patients with normal tension glaucoma (NTG) and autosomal-dominant optic atrophy (ADOA). (opticnervenetwork.com)
- Optic nerve heads were scanned by enhanced-depth imaging (EDI) optical coherence tomography (OCT). The LC curvature index (LCCI) and LC depth (LCD) on B-scan images obtained using EDI-OCT were measured at seven locations spaced equidistantly across the vertical optic disc diameter and compared among the NTG, ADOA, and control groups. (opticnervenetwork.com)
- Autosomal dominant optic atrophy (ADOA) is a rare genetic disease that causes progressive and irreversible vision loss in both eyes starting in the first decade of life. (ucdavis.edu)
- The findings of the study, published yesterday in the premier international scientific journal Nature Communications, reveal a novel molecular mechanism underlying the detrimental effects of uncontrolled mitophagy on neuronal survival that contributes to the development and progression of Autosomal Dominant Optic Atrophy (ADOA). (forth.gr)
- Neurophth Therapeutics today announced the Australian Therapeutic Goods Administration (TGA) has registered and approved its candidate drug, NFS-05, for clinical trials targeting autosomal dominant optic atrophy (ADOA). (ophthalmologytimes.com)
- According to the company, ADOA is an autosomal dominant inherited optic neuropathy, and about 80% of ADOA is caused by mutations in the OPA1 gene. (ophthalmologytimes.com)
- In April, the Company received authorization of its Clinical Trial Application (CTA) by the United Kingdom Medicines and Healthcare products Regulatory Agency (MHRA) to initiate a Phase 1 study (OSPREY) of STK-002 for the treatment of autosomal dominant optic atrophy (ADOA), the most common inherited optic nerve disorder. (stoketherapeutics.com)
- Here, we report the results of a comprehensive study on OPA3 mutations, including the mutation spectrum and its prevalence in a large cohort of OPA1-negative autosomal dominant optic atrophy (ADOA) patients, the associated clinical phenotype and the functional characterisation of a newly identified OPA3 mutant. (uni-muenchen.de)
- Autosomal dominant optic atrophy (ADOA), caused by mutations in OPA1, is a neurodegenerative disease affecting mainly retinal ganglion cells (RGCs). (omicsdi.org)
- Autosomal Dominant Optic Atrophy (ADOA) is the most common inherited optic atrophy where vision impairment results from specific loss of retinal ganglion cells of the optic nerve. (omicsdi.org)
- Autosomal dominant optic atrophy (ADOA), a form of progressive bilateral blindness due to loss of retinal ganglion cells and optic nerve deterioration, arises predominantly from mutations in the nuclear gene for the mitochondrial GTPase, OPA1. (omicsdi.org)
Recessive9
- SPG11 is inherited in an autosomal recessive manner. (nih.gov)
- Kjellin syndrome is characterized by retinal degeneration, autosomal recessive hereditary spastic paraplegia, and thin corpus callosum initially associated with spastic paraplegia 15 (SPG15) but more often occurring in individuals with SPG11. (nih.gov)
- Clinically, testing of GJB2 and GJB6 plays a prominent role in diagnosis and genetic counseling because mutations in these genes account for more than 50% of severe-to-profound autosomal recessive nonsyndromic deafness in many world populations. (nature.com)
- A genetic hearing loss may be inherited in an autosomal dominant, autosomal recessive, or X-linked Mendelian manner, or through the maternal lineage by mitochondrial inheritance. (nature.com)
- Several autosomal recessive forms have also been identified, including type A4 and an axial type associated with retinitis pigmentosa and optic atrophy. (orpha.net)
- The majority are inherited in an autosomal dominant manner but recessive and semidominant kindreds have been described. (bmj.com)
- Alternatively, DI may be idiopathic or inherited as either an autosomal dominant or an autosomal recessive trait (locus 20p13). (medscape.com)
- Nephrogenic DI arises from defective or absent receptor sites at the cortical collecting duct segment of the nephron (X-linked, vasopressin V2 receptor deficiency, locus Xq28) or defective or absent aquaporin, the protein that transports water at the collecting duct (autosomal recessive, locus 12q13). (medscape.com)
- [ 1 , 2 ] Eight mutations on AQP2 gene are associated with autosomal dominant nephrogenic DI, and 32 mutations are associated with autosomal recessive nephrogenic DI. (medscape.com)
Form of autosomal dominant optic a2
- Autosomal dominant optic atrophy and cataract is one form of autosomal dominant optic atrophy, a group of conditions that are estimated to affect 1 in 30,000 people worldwide, and approximately 1 in 10,000 people in Denmark. (medlineplus.gov)
- Interestingly, MFN2 shows functional overlap with the OPA1 gene, the protein underlying the most common form of autosomal dominant optic atrophy. (neuroophthalmology.ca)
OPA110
- Dominant optic atrophy (DOA) in particular has been traced to mutations in the GTPase domain of OPA1, leading to sensorineural hearing loss, ataxia, sensorimotor neuropathy, progressive external ophthalmoplegia, and mitochondrial myopathy. (wikipedia.org)
- OPA1, the gene responsible for autosomal dominant optic atrophy, represents a good candidate gene for normal-tension glaucoma (NTG). (nih.gov)
- The most relevant proteins involved in the mitochondrial fusion process are three GTPase dynamin-like proteins: mitofusin 1 (MFN1) and 2 (MFN2), located in the outer mitochondrial membrane, and optic atrophy protein 1 (OPA1), in the inner membrane. (centrodinoferrari.com)
- An expanding number of degenerative disorders are associated with mutations in the genes encoding MFN2 and OPA1, including Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy. (centrodinoferrari.com)
- The reduction in OPA1 protein function leads to mitochondrial fragmentation, and increased instability of the mitochondrial respiratory chain complex, which damages mitochondrial function and ultimately results in RGC cell death and optic nerve atrophy. (ophthalmologytimes.com)
- The most commonly associated phenotype with OPA1 mutations is heterozygous optic atrophy, a heterozygous dominant trait that causes reduced visual clarity and sometimes blindness. (thermofisher.com)
- Purpose: To investigate whether recently described polymorphisms in the optic atrophy 1 gene (OPA1) are associated with primary open-angle glaucoma (POAG) with elevated intraocular pressure in the Caucasian, African-American, and Ghanaian (West African) populations. (elsevierpure.com)
- Optic atrophy gene 1 (OPA1) is an inner membrane protein important for mitochondrial fusion. (omicsdi.org)
- Opa1(enu/+) mice show a slow progressive loss of RGCs, activation of astroglia and microglia, and pronounced mitochondrial fission in optic nerve heads as found by electron tomography. (omicsdi.org)
- Mitochondrial oxidative phosphorylation compensation may preserve vision in patients with OPA1-linked autosomal dominant optic atrophy. (omicsdi.org)
Retinal gangl2
- form the optic nerves, so when retinal ganglion cells die, the optic nerves atrophy and cannot transmit visual information to the brain. (medlineplus.gov)
- In patients, the disease primarily affects the retinal ganglion cells (RGCs) and causes optic nerve atrophy and visual loss. (ox.ac.uk)
Caused by mutations3
- Autosomal dominant optic atrophy and cataract is caused by mutations in a gene called OPA3 . (medlineplus.gov)
- Zuchner S, et al: Axonal neuropathy with optic atrophy is caused by mutations in mitofusin 2. (neuroophthalmology.ca)
- In summary, our study provides new insights into the clinical spectrum and the pathogenesis of dominant optic atrophy caused by mutations in the OPA3 gene. (uni-muenchen.de)
Transmitted in an autosomal dominant manner1
- Kozlowski type of spondylometaphyseal dysplasia is transmitted in an autosomal dominant manner, as well as the form of spondylometaphyseal dysplasia referred to as the 'corner fracture' or Sutcliffe type and the Algerian (or Schmidt) type. (orpha.net)
Pallor8
- Atrophy of these nerves causes an abnormally pale appearance (pallor) of the optic nerves, which can be seen only during an eye examination. (medlineplus.gov)
- Funduscopic examination can appear normal acutely, but disc edema can be present in approximately one-third of patients (particularly those with anterior optic neuritis).1, 2 Optic disc pallor is generally seen weeks to months following onset of typical optic neuritis. (clevelandclinic.org)
- Degenerated axons lose this optical property, explaining the pallor in optic atrophy. (medscape.com)
- The company also noted that patients diagnosed with the disease present with bilateral, slowly progressing visual impairment, temporal pallor of the optic disc, central visual field defects, and abnormalities in color vision. (ophthalmologytimes.com)
- This 47 year-old woman was seen for bilateral optic disc pallor. (neuroophthalmology.ca)
- Examination by a neurologist documented mild temporal pallor of the optic discs, Automated perimetry 5 and 4 years ago showed some scattered relative depression OS, and visual evoked potentials showed prolonged p100 latencies bilaterally. (neuroophthalmology.ca)
- Fundoscopy shows optic discs with diffuse pallor and cupping. (neuroophthalmology.ca)
- 2011). Other symptoms include central or near central scotomas, tritanopia, variable degree of ptosis, central visual field defects and/or ophthalmalgia and optic nerve pallor. (preventiongenetics.com)
Mutations6
- It is unclear how OPA3 gene mutations lead to cataracts and other eye problems that can occur in autosomal dominant optic atrophy and cataracts. (medlineplus.gov)
- Mutations in this gene have been implicated in dominant optic atrophy (DOA), leading to loss in vision, hearing, muscle contraction, and related dysfunctions. (wikipedia.org)
- Mutations in this gene have been associated with optic atrophy type 1, which is a dominantly inherited optic neuropathy resulting in progressive loss of visual acuity, leading in many cases to legal blindness. (wikipedia.org)
- Mutations in the ACO2 gene were identified in patients suffering from a broad range of symptoms, including optic nerve atrophy, cortical atrophy, cerebellar atrophy, hypotonia, seizures and intellectual disabilities. (huji.ac.il)
- Mutations in OPA3 have been reported in patients with autosomal dominant optic atrophy plus cataract and Costeff syndrome. (uni-muenchen.de)
- Comparison of the clinical phenotypes suggests that OPA3 mutations can additionally evoke hearing loss and by that extend the clinical manifestation of OPA3-associated optic atrophy. (uni-muenchen.de)
Pigmentary retinal degeneration1
- 1993). The Complicated form of the HSP shows additional neurological signs such as amyotrophy, mental retardation, pigmentary retinal degeneration, optic atrophy, extrapyramidal features, cerebellar ataxia, ichthyosis etc. (preventiongenetics.com)
Mutation3
- Our most advanced investigational gene therapy drug candidate, NR082, used for the treatment of Leber's hereditary optic neuropathy (LHON) associated with mtND4 mutation (ND4-LHON), has been granted orphan drug designation (ODD) by the U.S. FDA and the European Medicines Agency (EMA). (ophthalmologytimes.com)
- Our study reveals that a monoallelic mutation in ACO2 is sufficient to promote mitochondrial dysfunction and increased vulnerability to oxidative stress as main drivers of cell death related to optic nerve atrophy. (huji.ac.il)
- An autosomal dominant condition caused by mutation(s) in the CHAMP1 gene, encoding chromosome alignment-maintaining phosphoprotein 1. (nih.gov)
Regarding optic nerve1
- Visual evoked potentials (VEPs) can also provide valuable information regarding optic nerve impairment in ON. (clevelandclinic.org)
Neuropathy11
- Some people with autosomal dominant optic atrophy and cataract develop disturbances in the function of other nerves (neuropathy) besides the optic nerves. (medlineplus.gov)
- It is likely that nerve cells in other parts of the body are similarly affected by dysfunctional mitochondria, resulting in the signs and symptoms of neuropathy in individuals with autosomal dominant optic atrophy and cataract. (medlineplus.gov)
- Newly diagnosed with Autosomal dominant optic atrophy and peripheral neuropathy? (globalgenes.org)
- The presence of hemorrhages or exudates on funduscopic examination is more suggestive of other, non-demyelinating etiologies of optic neuropathy and warrants ophthalmology evaluation. (clevelandclinic.org)
- Anterior ischemic optic neuropathy (AION), arteritic or nonarteritic. (clevelandclinic.org)
- In conditions with primary optic atrophy (eg, pituitary tumor, optic nerve tumor, traumatic optic neuropathy, multiple sclerosis), optic nerve fibers degenerate in an orderly manner and are replaced by columns of glial cells without alteration in the architecture of the optic nerve head. (medscape.com)
- Vision loss in patients with Leber hereditary optic neuropathy typically begins between 15 and 35 years (range, 1 to 80 years). (msdmanuals.com)
- Some patients with Leber hereditary optic neuropathy have cardiac conduction defects. (msdmanuals.com)
- Voo I, et al: Hereditary motor and sensory neuropathy type VI with optic atrophy. (neuroophthalmology.ca)
- Patients with symptoms suggestive of inherited optic neuropathy are candidates. (preventiongenetics.com)
- Optic Atrophy (OA) is the most prevalent inherited optic neuropathy besides Leber's hereditary optic neuropathy (LHON). (preventiongenetics.com)
Mitochondrial3
- The results provide support to growing evidence that the melanopsin-expressing RGCs are protected in mitochondrial optic neuropathies. (ox.ac.uk)
- Mitochondrial oxidative phosphorylation in autosomal dominant optic atrophy. (omicsdi.org)
- Increased mitochondrial fission and volume density by blocking glutamate excitotoxicity protect glaucomatous optic nerve head astrocytes. (omicsdi.org)
Neuropathies4
- Optic neuropathies are common causes of blindness worldwide, affect the lives of millions, and currently lack effective treatments to restore vision," said Thomasy. (ucdavis.edu)
- Hereditary optic neuropathies result from genetic defects that cause vision loss and occasionally cardiac or neurologic abnormalities. (msdmanuals.com)
- It is believed to be the most common of the hereditary optic neuropathies, with prevalence in the range of 1:10,000 to 1:50,000. (msdmanuals.com)
- Identification of genetic variants that enable this response may provide novel therapeutic insights into OXPHOS compensation for preventing vision loss in optic neuropathies. (omicsdi.org)
Cataract3
- Autosomal dominant optic atrophy and cataract is an eye disorder that is characterized by impaired vision. (medlineplus.gov)
- Several abnormalities contribute to impaired vision in people with autosomal dominant optic atrophy and cataract. (medlineplus.gov)
- A form of optic atrophy called optic atrophy type 1 accounts for most cases, while autosomal dominant optic atrophy and cataract is thought to represent only a few percent of autosomal dominant optic atrophy cases. (medlineplus.gov)
Hereditary2
- Using data from the Danish Family Register of Hereditary Eye Diseases, the minimum prevalence rate was estimated to 1:12.301, making DOA the most common hereditary optic atrophy. (nih.gov)
- Diagnosis of dominant optic atrophy and Leber hereditary optic atrophy is mainly clinical. (msdmanuals.com)
Bilateral1
- Bilateral optic nerve atrophy begins at an early age but is very slowly progressive, with visual loss noticeable by the patient by age 24 to 30 years. (mhmedical.com)
Retinitis Pigmentosa1
- Lastly, some moderate forms are at present not well classified and other forms have also been identified, including type A4, and an axial type associated with retinitis pigmentosa and optic atrophy (see these terms). (orpha.net)
Phenotype2
- Usually, this phenotype is attributed to the degeneration of optic nerve fibers. (thermofisher.com)
- The expanding clinical phenotype of Bosch-Boonstra-Schaaf optic atrophy syndrome: 20 new cases and possible genotype-phenotype correlations. (nih.gov)
Disease3
- Optic atrophy is the final common morphologic endpoint of disease process that causes degeneration of axons of the ganglion cells. (medscape.com)
- Nonhuman primates have similar optic nerve and retinal anatomy to humans, making them a uniquely powerful model for this disease. (ucdavis.edu)
- Comparison of CSF biomarkers in Down syndrome and autosomal dominant Alzheimer's disease: a cross-sectional study. (nih.gov)
Pathogenesis1
- IMBB Researchers and Scientists from the University of Padova uncover a novel pathogenesis mechanism for Autosomal Dominant Optic Atrophy, an incurable, visual loss disorder. (forth.gr)
Abnormalities1
- Most patients with dominant optic atrophy have no associated neurologic abnormalities, although nystagmus and hearing loss have been reported. (msdmanuals.com)
Dominantly inherited1
- HSMN, type VI, which we believe this patient to have, is an autosomal dominantly inherited axonal sensorimotor polyneuropathy associated with optic atrophy. (neuroophthalmology.ca)
Inheritance1
- HSMN with spastic paraparesis, or HSMN with optic atrophy) and/or patterns of inheritance (i.e. (neuroophthalmology.ca)
Genetic1
- Now that genetic testing is available, it can be performed to confirm the diagnosis of autosomal dominant OPCAs. (medscape.com)
Clinically3
- [ 1 ] Clinically, optic atrophy manifests as changes in the color and the structure of the optic disc (cupping) associated with variable degrees of visual dysfunction. (medscape.com)
- Clinically, the light incident from the ophthalmoscope undergoes total internal reflection through the axonal fibers, and subsequent reflection from the capillaries on the disc surface gives rise to the characteristic yellow-pink color of a healthy optic disc. (medscape.com)
- Sixty-two patients from three large Danish families with autosomal dominant optic atrophy were clinically examined, and retrospective follow-up was made on 30 patients. (nih.gov)
Disorders1
- Available at https://www.ninds.nih.gov/health-information/disorders/olivopontocerebellar-atrophy . (medscape.com)
Common3
- Optic neuritis (ON) is a common manifestation of multiple sclerosis (MS), and refers to inflammation of the optic nerve. (clevelandclinic.org)
- The most common presentation is that of an autosomal dominant demyelinating sensorimotor polyneuropathy (CMT 1) with the second most common presentation being an autosomal dominant axonal sensorimotor polyneuropathy (CMT 2). (neuroophthalmology.ca)
- The most common OA is inherited in an autosomal dominant (AD) mode (DOA). (preventiongenetics.com)
Axonal1
- OCT evaluates the optic nerve axonal integrity by measurement of the retinal nerve fiber layer (RNFL), and is generally used to evaluate for evidence of prior ON. (clevelandclinic.org)
Symptoms2
- Care of olivopontocerebellar atrophy (OPCA) is directed to the treatment of symptoms. (medscape.com)
- Typical symptoms of relapses may be referable to demyelinating pathology involving the optic nerves (e.g. optic neuritis), brainstem (e.g. internuclear ophthalmoplegia) or spinal cord (e.g. partial myelitis), although non-specific symptoms referable to the cerebral hemispheres or other brain regions can also occur (Katz Sand and Lublin, 2013). (medscape.com)
Neuritis7
- What are the typical clinical features of optic neuritis? (clevelandclinic.org)
- The pain that occurs with optic neuritis is usually ocular, retroocular, periorbital, or a frontal headache. (clevelandclinic.org)
- How to approach the patient with suspected optic neuritis? (clevelandclinic.org)
- Imaging modalities used in the diagnosis of optic neuritis include orbital MRI and optical coherence tomography (OCT). These tools can be particularly helpful if the clinical history or physical examination findings are atypical for ON. (clevelandclinic.org)
- VEPs evaluate optic nerve function by calculating P100 latency and amplitude, which are generally abnormal in the setting of acute and remote optic neuritis. (clevelandclinic.org)
- Prolonged P100 latency is a characteristic of remote optic neuritis. (clevelandclinic.org)
- What is the neurologic differential diagnosis of optic neuritis? (clevelandclinic.org)
Peripheral1
- Thus, the optic nerve behaves more like a white matter tract rather than a true peripheral nerve. (medscape.com)
Diagnosis2
- therefore, family members must be evaluated early if a diagnosis of autosomal dominant OPCA is made. (medscape.com)
- BACKGROUND: The importance of early diagnosis of 5q-Spinal muscular atrophy (5q-SMA) has heightened as early intervention can significantly improve clinical outcomes. (bvsalud.org)
Slowly1
- It is characterized by slowly progressive weakness and atrophy of the feet, calves, hands and forearms. (neuroophthalmology.ca)
Fibroblasts1
- The optic nerve head sits at a major transition between an area of high pressure to an area of low pressure (intracranial pressure) and is composed of 4 types of cells: ganglion cell axons, astrocytes, capillary-associated cells, and fibroblasts. (medscape.com)
Progresses1
- As dysphagia progresses with olivopontocerebellar atrophy (OPCA), a pureed diet or enteral feeding may be required. (medscape.com)
Nerve damage1
- Optic nerve damage is usually permanent and in some cases progressive. (msdmanuals.com)
Edema2
- OCT at onset of ON is also potentially confounded by edema of the optic disc, which may lead to overestimates of baseline RNFL.4 Ganglion cell layer (GCL) thickness, another OCT measure, is not confounded by disc edema but declines in a similar time frame to RNFL and therefore may be more useful as a baseline measurement. (clevelandclinic.org)
- In conditions with secondary optic atrophy (eg, papilledema, papillitis), the atrophy is secondary to disc edema (shown in the image below). (medscape.com)
Temporal1
- The entire optic disk or, at times, only the temporal portion is pale without visible vessels. (msdmanuals.com)