Dyskeratosis Congenita
Myotonia Congenita
Telomere Shortening
Telomerase
Leukoplakia
Telomere
Pachyonychia Congenita
Ribonucleoproteins, Small Nucleolar
Pigmentation Disorders
Nails, Malformed
Telomere-Binding Proteins
Nail Diseases
Hyperpigmentation
Bone Marrow Diseases
Anticipation, Genetic
Pancytopenia
Telomere Homeostasis
RNA
Ribonucleoproteins, Small Nuclear
Pedigree
Nails
Pseudouridine
Microcephaly
Mutation
Anemia, Aplastic
Rothmund-Thomson Syndrome
Nuclear Proteins
Leukoplakia, Oral
Cell Cycle Proteins
Anemia, Diamond-Blackfan
Genes, Dominant
Hydro-Lyases
Ectodermal Dysplasia
Skin Diseases
Fanconi Anemia
DAX-1 Orphan Nuclear Receptor
Darier Disease
Hemoglobinuria, Paroxysmal
X Chromosome
Myotonic Disorders
Mutation, Missense
Keratin-6
Keratoderma, Palmoplantar
Keratin-16
Keratin-17
Family Health
Heterozygote
Correction of bone marrow failure in dyskeratosis congenita by bone marrow transplantation. (1/143)
Dyskeratosis congenita is recognized by its dermal lesions and constitutional aplastic anemia in some cases. We report successful allogeneic bone marrow transplantation in two siblings with this disease from their sister, and their long term follow-up. We used reduced doses of cyclophosphamide and busulfan for conditioning instead of total body irradiation. Also, we report late adverse effects of transplantation which are not distinguishable from the natural course of disease. (+info)X-linked dyskeratosis congenita is predominantly caused by missense mutations in the DKC1 gene. (2/143)
Dyskeratosis congenita is a rare inherited bone marrow-failure syndrome characterized by abnormal skin pigmentation, nail dystrophy, and mucosal leukoplakia. More than 80% of patients develop bone-marrow failure, and this is the major cause of premature death. The X-linked form of the disease (MIM 305000) has been shown to be caused by mutations in the DKC1 gene. The gene encodes a 514-amino-acid protein, dyskerin, that is homologous to Saccharomyces cerevisiae Cbf5p and rat Nap57 proteins. By analogy to the homologues in other species, dyskerin is predicted to be a nucleolar protein with a role in both the biogenesis of ribosomes and, in particular, the pseudouridylation of rRNA precursors. We have determined the genomic structure of the DKC1 gene; it consists of 15 exons spanning a region of 15 kb. This has enabled us to screen for mutations in the genomic DNA, by using SSCP analysis. Mutations were detected in 21 of 37 additional families with dyskeratosis congenita that were analyzed. These mutations consisted of 11 different single-nucleotide substitutions, which resulted in 10 missense mutations and 1 putative splicing mutation within an intron. The missense change A353V was observed in 10 different families and was shown to be a recurring de novo event. Two polymorphisms were also detected, one of which resulted in the insertion of an additional lysine in the carboxy-terminal polylysine domain. It is apparent that X-linked dyskeratosis congenita is predominantly caused by missense mutations; the precise effect on the function of dyskerin remains to be determined. (+info)Dyskeratosis congenita caused by a 3' deletion: germline and somatic mosaicism in a female carrier. (3/143)
X-linked dyskeratosis congenita (DC) is a bone marrow failure syndrome caused by mutations in the DKC1 gene located at Xq28. By 20 years of age, most affected boys develop bone marrow failure, whereas female carriers show a skewed pattern of X-chromosome inactivation. The gene product, dyskerin, is homologous to a yeast protein involved in ribosomal RNA biogenesis, providing a unique insight into a cause of aplastic anemia. Whereas most causative mutations are single amino acid substitutions, and nonsense or frameshift mutations have not been observed, we present here a case of DC caused by a 2-kb deletion that removes the last exon of the gene. Normal levels of mRNA are produced from the deleted gene, with the transcripts using a cryptic polyadenylation site in the antisense strand of the adjacent MPP1 gene, normally located 1 kb downstream of DKC1 in a tail to tail orientation. The predicted truncated protein lacks a lysine-rich peptide that is less conserved than the rest of the dyskerin molecule and is dispensable in yeast, supporting the contention that it may retain some activity and that null mutations at this locus may be lethal. The affected boy had an unaffected brother with the same haplotype around the DKC1 gene and a sister who was heterozygous for the deletion. We conclude therefore that the mother must be a germline mosaic with respect to this deletion. Investigation of her blood cells and other somatic tissues showed that a small proportion of these cells also carried the deletion, making her a somatic mosaic and indicating that the deletion took place early in development. (+info)Dyskerin localizes to the nucleolus and its mislocalization is unlikely to play a role in the pathogenesis of dyskeratosis congenita. (4/143)
Mutations in the DKC1 gene are responsible for causing the bone marrow failure syndrome, dyskeratosis congenita (DKC; OMIM 305000). The majority of mutations identified to date are missense mutations and are clustered in exons 3, 4 and 11. It is predicted that the corresponding protein dyskerin is a nucleolar phosphoprotein which functions in both pseudo-uridylation and cleavage of precursor rRNA. Dyskerin contains multiple putative nuclear localization signals (NLSs) at the N-terminus (KKHKKKKERKS) and C-terminus [KRKR(X)(17)KKEKKKSKKDKKAK(X)(17)-KKKKKKKKAKEVELVSE]. By fusing dyskerin with the enhanced green fluorescent protein (EGFP) and by following a time course of expression in mammalian cell lines, we showed that full-length dyskerin initially localizes to the nucleoplasm and subsequently accumulates in the nucleoli. A co-localization to the coiled bodies was observed in some cells where dyskerin-EGFP had translocated to the nucleoli. Analysis of a series of mutant constructs indicated that whereas the most C-terminal lysine-rich clusters [KKEKKKS-KKDKKAK(X)(17)KKKKKKKKAKEVELVSE] influence the rate of nucleoplasmic and nucleolar accumulation, the KRKR sequence is primarily responsible for the nuclear import. Nucleolar localization was maintained when either the N- or C-terminal motifs were mutated, but not when all NLSs were removed. We conclude that the intranuclear localization of dyskerin is accomplished by the synergistic effect of a number of NLSs and that the nucleolar localization signals are contained within the NLSs. Further, examination of dyskerin-EGFP fusions mimicking mutations detected in patients indicated that the intracellular mislocalization of dyskerin is unlikely to cause DKC. (+info)X-linked dyskeratosis congenita: restrictive pulmonary disease and a novel mutation. (5/143)
Dyskeratosis congenita (DC) is a rare inherited multisystem disorder characterised by lesions of the skin and appendages. Bone marrow failure occurs in 80% of patients. The gene for the X-linked form of DC has been identified on Xq28 and designated as DKC1. Pulmonary manifestations have rarely been reported. It is not known whether there is a respiratory disease peculiar to these patients and, if so, whether it is associated with a specific genetic mutation. A 40 year old Egyptian man with pulmonary disease and his symptom free 35 year old brother both presented with mucocutaneous lesions characteristic of DC. In the older brother chest imaging revealed generalised intralobular interstitial thickening and honeycombing. Pulmonary function tests showed a restrictive pattern. Open lung biopsy specimens of lung tissue showed various degrees of fibrosis consistent with usual interstitial pneumonia of chronic idiopathic pulmonary fibrosis. The younger brother was free of pulmonary lesions. Both had a novel missense mutation 5C-->T in exon 1 of the DKC1 gene. It is concluded that pulmonary disease in DC may be underestimated, possibly because most patients die at an early age of bone marrow failure. No relationship between genotype and phenotype could be established in the patients studied. The genetic diagnosis of DC is now available, which may enable it to be diagnosed in patients with restrictive pulmonary disease and minimal cutaneous signs. (+info)Telomerase in the human organism. (6/143)
The intent of this review is to describe what is known and unknown about telomerase in somatic cells of the human organism. First, we consider the telomerase enzyme. Human telomerase ribonucleoproteins undergo at least three stages of cellular biogenesis: accumulation, catalytic activation and recruitment to the telomere. Next, we describe the patterns of telomerase regulation in the human soma. Telomerase activation in some cell types appears to offset proliferation-dependent telomere shortening, delaying but not defeating the inherent mitotic clock. Finally, we elaborate the connection between telomerase misregulation and human disease, in the contexts of inappropriate telomerase activation and telomerase deficiency. We discuss how our current perspectives on telomerase function could be applied to improving human health. (+info)Increased mortality rate and not impaired ribosomal biogenesis is responsible for proliferative defect in dyskeratosis congenita cell lines. (7/143)
X-linked dyskeratosis congenita is a rare inherited disorder mainly characterized by progressive changes in proliferating epidermal, mucosal, and bone marrow tissues that commonly emerge after 10 y of life. It is caused by mutations of the DKC1 gene, which codes for dyskerin, a protein that may play a role in ribosomal biogenesis. In order to verify whether the defects of proliferating tissues observed in dyskeratosis congenita are due to an altered ribosome synthesis, we studied ribosomal biogenesis in relation to cell proliferation in two lymphoblastoid cell lines from dyskeratosis congenita patients and in one control line. We observed that in the dyskeratosis congenita cell lines the rRNA transcription and maturation and proliferative capability remained unimpaired. Increasing the number of cell cycles, however, leads to a steep rise in the apoptotic fraction of dyskeratosis congenita cells, which is not observed in controls. These findings demonstrate that whereas dyskeratosis congenita cell lines do not display proliferation defects, they do show progressively increasing levels of apoptosis in relation to the number of cell divisions. This concept is consistent with (i) the delayed onset of dyskeratosis congenita proliferating-tissue defects, which do not emerge during embrional development as would be expected with ribosomal biogenesis alterations, and (ii) with the increasing severity of the proliferating-tissue defects over time. (+info)Targeted disruption of Dkc1, the gene mutated in X-linked dyskeratosis congenita, causes embryonic lethality in mice. (8/143)
Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome associated with increased cancer susceptibility. The X-linked form is due to mutations in the DKC1 gene encoding dyskerin, a nucleolar protein predicted to be involved in rRNA processing and associated with the telomerase complex. Available evidence suggests the pathology of DC is due to telomerase defects. We have used the inducible Cre/loxP system to produce deletions in the murine Dkc1 gene in early embryogenesis. A large deletion lacking exons 12-15 and a small deletion lacking only the last exon, were produced. We found both deletions showed a parent-of-origin effect with 100% embryonic lethality when the mutation occurred on the maternal Dkc1. Embryonic analysis at day E7.5 and E9.5 showed no male embryos carrying either deletion whereas females with maternally derived deletions died around day E9.5, with degeneration of the extra embryonic tissue, in which the paternal X-chromosome is inactivated. Female mice carrying the deletion in the paternally derived Dkc1 show extreme skewing of X-inactivation with the wild type X-chromosome active in all cells. Since mice with no telomerase are viable in the first generations the lethality we observe is unlikely to be due to the effects of mutated dyskerin on telomerase activity. (+info)Dyskeratosis congenita is a rare genetic disorder that affects the bone marrow's ability to produce blood cells and can also affect other parts of the body, such as the skin, nails, and mucous membranes. It is characterized by the triad of abnormal skin pigmentation, nail dystrophy, and leukoplakia (white patches) in the mouth. People with dyskeratosis congenita are also at an increased risk of developing bone marrow failure, cancer, and pulmonary fibrosis. The disorder is caused by mutations in genes involved in the maintenance of telomeres, which are the protective caps on the ends of chromosomes that shorten as cells divide. These mutations can lead to premature shortening of telomeres and cellular aging, resulting in the symptoms of dyskeratosis congenita.
Myotonia Congenita is a genetic muscle disorder characterized by delayed relaxation after voluntary muscle contraction, leading to stiffness or difficulty in relaxing the muscles following use. This muscle stiffness is called myotonia and can be aggravated by voluntary muscle action, such as handgrip or walking, and also occurs after periods of rest.
There are two main forms of Myotonia Congenita: Thomsen's disease (autosomal dominant inheritance) and Becker's disease (autosomal recessive inheritance). The disorder is caused by mutations in the CLCN1 gene, which encodes a chloride channel that helps regulate muscle excitability.
Myotonia Congenita primarily affects skeletal muscles, causing stiffness and cramping, but it does not typically affect muscle strength or size. Symptoms usually begin in childhood and may improve with repeated muscle use (warm-up phenomenon). Treatment options include medication to reduce muscle stiffness and physical therapy to maintain muscle flexibility and strength.
Telomere shortening is the gradual loss of repetitive DNA sequences and associated proteins from the ends of chromosomes that occurs naturally as cells divide. Telomeres are protective caps at the ends of chromosomes, which prevent the loss of genetic information during cell division. However, each time a cell divides, its telomeres become slightly shorter. When telomeres reach a critically short length, the cell can no longer divide and becomes senescent or dies. This process is thought to contribute to aging and age-related diseases, as well as to the development of cancer.
Telomerase is an enzyme that adds repetitive DNA sequences (telomeres) to the ends of chromosomes, which are lost during each cell division due to the incomplete replication of the ends of linear chromosomes. Telomerase is not actively present in most somatic cells, but it is highly expressed in germ cells and stem cells, allowing them to divide indefinitely. However, in many types of cancer cells, telomerase is abnormally activated, which leads to the maintenance or lengthening of telomeres, contributing to their unlimited replicative potential and tumorigenesis.
Leukoplakia is a medical term used to describe a white or gray patch that develops on the mucous membranes lining the inside of the mouth. These patches are typically caused by excessive cell growth and cannot be easily scraped off. Leukoplakia is often associated with long-term tobacco use, including smoking and chewing tobacco, as well as alcohol consumption. While most cases of leukoplakia are benign, a small percentage can develop into oral cancer, so it's essential to have any suspicious patches evaluated by a healthcare professional.
A telomere is a region of repetitive DNA sequences found at the end of chromosomes, which protects the genetic data from damage and degradation during cell division. Telomeres naturally shorten as cells divide, and when they become too short, the cell can no longer divide and becomes senescent or dies. This natural process is associated with aging and various age-related diseases. The length of telomeres can also be influenced by various genetic and environmental factors, including stress, diet, and lifestyle.
Pachyonychia Congenita (PC) is a rare genetic disorder characterized by thickened and abnormally shaped nails, painful blisters on the skin, and thickened palms and soles. The condition is caused by mutations in genes responsible for producing keratin proteins, which are essential components of our skin, hair, and nails.
There are two main types of PC: Type 1 (Jadassohn-Lewandowsky syndrome) and Type 2 (Jackson-Lawler syndrome). Both types have similar symptoms but may vary in severity. The symptoms typically appear at birth or within the first few years of life.
The medical definition of Pachyonychia Congenita includes:
1. Nails: Thickening and overcurvature of the nails, often with a yellow-white discoloration.
2. Skin: Formation of blisters and calluses on pressure points such as hands, feet, knees, and elbows. These blisters can be painful and may lead to secondary infections.
3. Palms and soles: Hyperkeratosis (thickening) of the skin on the palms and soles, causing discomfort or pain while walking or performing manual tasks.
4. Mucous membranes: In some cases, the condition can also affect the mucous membranes, leading to oral lesions and thickened vocal cords.
5. Genetics: PC is an autosomal dominant disorder, meaning that only one copy of the mutated gene inherited from either parent is sufficient to cause the disease. However, some cases may result from spontaneous mutations in the affected individual.
Small nucleolar ribonucleoproteins (snoRNPs) are a type of ribonucleoprotein complex found in the nucleus of eukaryotic cells. They play a crucial role in the post-transcriptional modification of ribosomal RNA (rRNA) and small nuclear RNA (snRNA). Specifically, snoRNPs are responsible for guiding the addition of methyl groups to specific nucleotides in rRNA and snRNA, a process known as 2'-O-methylation.
Small nucleolar ribonucleoproteins are composed of two main components: a small nucleolar RNA (snoRNA) and several proteins. The snoRNA molecule contains a conserved sequence that base-pairs with the target rRNA or snRNA, forming a structure that positions the methyl group donor enzyme, methyltransferase, in close proximity to the nucleotide to be modified.
Small nucleolar ribonucleoproteins are classified into two main categories based on their snoRNA components: box C/D snoRNPs and box H/ACA snoRNPs. Box C/D snoRNPs guide 2'-O-methylation, while box H/ACA snoRNPs are responsible for pseudouridination, another type of RNA modification.
Overall, small nucleolar ribonucleoproteins play a critical role in maintaining the stability and functionality of rRNAs and snRNAs, which are essential components of the translation and splicing machinery in eukaryotic cells.
Pigmentation disorders are conditions that affect the production or distribution of melanin, the pigment responsible for the color of skin, hair, and eyes. These disorders can cause changes in the color of the skin, resulting in areas that are darker (hyperpigmentation) or lighter (hypopigmentation) than normal. Examples of pigmentation disorders include melasma, age spots, albinism, and vitiligo. The causes, symptoms, and treatments for these conditions can vary widely, so it is important to consult a healthcare provider for an accurate diagnosis and treatment plan.
Medical definitions of "malformed nails" may vary, but generally, it refers to a condition where the nails are abnormally formed or shaped. This can include various deformities such as:
1. Koilonychia: Also known as "spoon nails," where the nails appear scooped out and concave.
2. Pterygium: A condition where skin grows over the nail, causing it to adhere to the finger.
3. Onychogryphosis: Also known as "ram's horn nails," where the nails become thick, curved, and overgrown.
4. Brachyonychia: Shortened nails that do not grow normally.
5. Onychauxis: Thickening of the nails.
6. Leukonychia: White spots or lines on the nails.
7. Beau's lines: Indentations across the nails, often caused by a previous illness or injury.
8. Pitting: Small depressions or holes in the nails.
9. Cracking or splitting of the nails.
These nail abnormalities can be caused by various factors such as genetics, fungal infections, trauma, nutritional deficiencies, and underlying medical conditions.
Telomere-binding proteins are specialized proteins that bind to the telomeres, which are the repetitive DNA sequences found at the ends of chromosomes. These proteins play a crucial role in protecting the structural integrity and stability of chromosomes by preventing the degradation of telomeres during cell division and preventing the chromosomes from being recognized as damaged or broken.
One of the most well-known telomere-binding proteins is called TRF2 (telomeric repeat-binding factor 2), which helps to maintain the structure of the telomere "T-loop" and prevent the activation of DNA repair mechanisms that can lead to chromosomal instability. Another important telomere-binding protein is called POT1 (protection of telomeres 1), which specifically binds to the single-stranded overhang of the telomere and helps to regulate the activity of telomerase, an enzyme that adds DNA repeats to the ends of chromosomes during cell division.
Mutations in telomere-binding proteins have been linked to a variety of human diseases, including premature aging disorders, cancer, and bone marrow failure syndromes. Therefore, understanding the function and regulation of these proteins is an important area of research in molecular biology and genetics.
Nail diseases, also known as onychopathies, refer to a group of medical conditions that affect the nail unit, which includes the nail plate, nail bed, lunula, and surrounding skin (nail fold). These diseases can be caused by various factors such as fungal infections, bacterial infections, viral infections, systemic diseases, trauma, and neoplasms.
Some common examples of nail diseases include:
1. Onychomycosis - a fungal infection that affects the nail plate and bed, causing discoloration, thickening, and crumbling of the nail.
2. Paronychia - an infection or inflammation of the nail fold, caused by bacteria or fungi, resulting in redness, swelling, and pain.
3. Ingrown toenails - a condition where the nail plate grows into the surrounding skin, causing pain, redness, and infection.
4. Onycholysis - a separation of the nail plate from the nail bed, often caused by trauma or underlying medical conditions.
5. Psoriasis - a systemic disease that can affect the nails, causing pitting, ridging, discoloration, and onycholysis.
6. Lichen planus - an inflammatory condition that can affect the skin and nails, causing nail thinning, ridging, and loss.
7. Melanonychia - a darkening of the nail plate due to pigmentation, which can be benign or malignant.
8. Brittle nails - a condition characterized by weak, thin, and fragile nails that easily break or split.
9. Subungual hematoma - a collection of blood under the nail plate, often caused by trauma, resulting in discoloration and pain.
10. Tumors - abnormal growths that can develop in or around the nail unit, ranging from benign to malignant.
Accurate diagnosis and treatment of nail diseases require a thorough examination and sometimes laboratory tests, such as fungal cultures or skin biopsies. Treatment options vary depending on the underlying cause and may include topical or oral medications, surgical intervention, or lifestyle modifications.
Hyperpigmentation is a medical term that refers to the darkening of skin areas due to an increase in melanin, the pigment that provides color to our skin. This condition can affect people of all races and ethnicities, but it's more noticeable in those with lighter skin tones.
Hyperpigmentation can be caused by various factors, including excessive sun exposure, hormonal changes (such as during pregnancy), inflammation, certain medications, and underlying medical conditions like Addison's disease or hemochromatosis. It can also result from skin injuries, such as cuts, burns, or acne, which leave dark spots known as post-inflammatory hyperpigmentation.
There are several types of hyperpigmentation, including:
1. Melasma: This is a common form of hyperpigmentation that typically appears as symmetrical, blotchy patches on the face, particularly the forehead, cheeks, and upper lip. It's often triggered by hormonal changes, such as those experienced during pregnancy or while taking birth control pills.
2. Solar lentigos (age spots or liver spots): These are small, darkened areas of skin that appear due to prolonged sun exposure over time. They typically occur on the face, hands, arms, and decolletage.
3. Post-inflammatory hyperpigmentation: This type of hyperpigmentation occurs when an injury or inflammation heals, leaving behind a darkened area of skin. It's more common in people with darker skin tones.
Treatment for hyperpigmentation depends on the underlying cause and may include topical creams, chemical peels, laser therapy, or microdermabrasion. Preventing further sun damage is crucial to managing hyperpigmentation, so wearing sunscreen with a high SPF and protective clothing is recommended.
Bone marrow diseases, also known as hematologic disorders, are conditions that affect the production and function of blood cells in the bone marrow. The bone marrow is the spongy tissue inside bones where all blood cells are produced. There are various types of bone marrow diseases, including:
1. Leukemia: A cancer of the blood-forming tissues, including the bone marrow. Leukemia causes the body to produce large numbers of abnormal white blood cells, which can crowd out healthy blood cells and impair their function.
2. Lymphoma: A cancer that starts in the lymphatic system, which is part of the immune system. Lymphoma can affect the bone marrow and cause an overproduction of abnormal white blood cells.
3. Multiple myeloma: A cancer of the plasma cells, a type of white blood cell found in the bone marrow. Multiple myeloma causes an overproduction of abnormal plasma cells, which can lead to bone pain, fractures, and other complications.
4. Aplastic anemia: A condition in which the bone marrow does not produce enough new blood cells. This can lead to symptoms such as fatigue, weakness, and an increased risk of infection.
5. Myelodysplastic syndromes (MDS): A group of disorders in which the bone marrow does not produce enough healthy blood cells. MDS can lead to anemia, infections, and bleeding.
6. Myeloproliferative neoplasms (MPNs): A group of disorders in which the bone marrow produces too many abnormal white or red blood cells, or platelets. MPNs can lead to symptoms such as fatigue, itching, and an increased risk of blood clots.
Treatment for bone marrow diseases depends on the specific condition and its severity. Treatment options may include chemotherapy, radiation therapy, stem cell transplantation, or targeted therapies that target specific genetic mutations.
Genetic anticipation is a phenomenon observed in certain genetic disorders where the severity and/or age of onset of the disease tend to worsen in successive generations. This occurs due to an expansion of triplet repeat sequences (sequences of three consecutive DNA base pairs) in the affected gene, which can lead to an increased production of abnormal proteins associated with the disorder. The expanded repeats are more likely to be inherited when the parent who carries them is a female. Examples of genetic disorders that exhibit anticipation include Huntington's disease, myotonic dystrophy, and fragile X syndrome.
Pancytopenia is a medical condition characterized by a reduction in the number of all three types of blood cells in the peripheral blood: red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia). This condition can be caused by various underlying diseases, including bone marrow disorders, viral infections, exposure to toxic substances or radiation, vitamin deficiencies, and certain medications. Symptoms of pancytopenia may include fatigue, weakness, increased susceptibility to infections, and easy bruising or bleeding.
Telomere homeostasis refers to the balance between the processes that maintain or lengthen telomeres and those that shorten them. Telomeres are the protective caps at the ends of chromosomes, which progressively shorten each time a cell divides due to the inability of conventional DNA polymerase to fully replicate the ends of linear chromosomes.
The maintenance of telomere length is critical for maintaining genomic stability and preventing cellular senescence or apoptosis (programmed cell death). Telomere homeostasis involves several mechanisms, including the enzyme telomerase, which adds DNA repeats to the ends of telomeres, and other protective proteins that bind to telomeres and prevent their degradation.
On the other hand, processes such as oxidative stress, inflammation, and genotoxic agents can cause excessive telomere shortening, leading to cellular dysfunction and aging-related diseases. Therefore, maintaining telomere homeostasis is essential for healthy aging and preventing age-related diseases.
RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.
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.
Small nuclear ribonucleoproteins (snRNPs) are a type of ribonucleoprotein (RNP) found within the nucleus of eukaryotic cells. They are composed of small nuclear RNA (snRNA) molecules and associated proteins, which are involved in various aspects of RNA processing, particularly in the modification and splicing of messenger RNA (mRNA).
The snRNPs play a crucial role in the formation of spliceosomes, large ribonucleoprotein complexes that remove introns (non-coding sequences) from pre-mRNA and join exons (coding sequences) together to form mature mRNA. Each snRNP contains a specific snRNA molecule, such as U1, U2, U4, U5, or U6, which recognizes and binds to specific sequences within the pre-mRNA during splicing. The associated proteins help stabilize the snRNP structure and facilitate its interactions with other components of the spliceosome.
In addition to their role in splicing, some snRNPs are also involved in other cellular processes, such as transcription regulation, RNA export, and DNA damage response. Dysregulation or mutations in snRNP components have been implicated in various human diseases, including cancer, neurological disorders, and autoimmune diseases.
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.
In the context of medical terminology, "nails" primarily refer to the keratinous plates that are found at the tips of fingers and toes. These specialized structures are part of the outermost layer of the skin (epidermis) and are formed by a type of cells called keratinocytes. The nails serve to protect the delicate underlying tissues from trauma, and they also aid in tasks such as picking up small objects or scratching itches.
The medical term for fingernails and toenails is "unguis," which comes from Latin. Each nail consists of several parts:
1. Nail plate: The visible part of the nail that is hard and flat, made up of keratin.
2. Nail bed: The skin beneath the nail plate to which the nail plate is attached; it supplies blood to the nail.
3. Matrix: The area where new cells are produced for the growth of the nail plate; located under the cuticle and extends slightly onto the finger or toe.
4. Lunula: The crescent-shaped white area at the base of the nail plate, which is the visible portion of the matrix.
5. Cuticle: The thin layer of skin that overlaps the nail plate and protects the underlying tissue from infection.
6. Eponychium: The fold of skin that surrounds and covers the nail plate; also known as the "proximal nail fold."
7. Hyponychium: The area of skin between the free edge of the nail plate and the fingertip or toe tip.
8. Perionychiun: The skin surrounding the nail on all sides.
Understanding the anatomy and medical aspects of nails is essential for healthcare professionals, as various conditions can affect nail health, such as fungal infections, ingrown nails, or tumors.
Pseudouridine is a modified nucleoside that is formed through the enzymatic process of pseudouridylation, where a uracil base in RNA is replaced by a pseudouracil base. Pseudouridine is structurally similar to uridine, but the uracil base is linked to the ribose sugar at carbon-5 rather than carbon-1, which leads to altered chemical and physical properties. This modification can affect RNA structure, stability, and function, and has been implicated in various cellular processes such as translation, splicing, and gene regulation.
Arthrogryposis is a medical term that describes a condition characterized by the presence of multiple joint contractures at birth. A contracture occurs when the range of motion in a joint is limited, making it difficult or impossible to move the joint through its full range of motion. In arthrogryposis, these contractures are present in two or more areas of the body.
The term "arthrogryposis" comes from two Greek words: "arthro," meaning joint, and "gyros," meaning curved or bent. Therefore, arthrogryposis literally means "curving of the joints."
There are many different types of arthrogryposis, each with its own specific set of symptoms and causes. However, in general, arthrogryposis is caused by decreased fetal movement during pregnancy, which can be due to a variety of factors such as genetic mutations, nervous system abnormalities, or environmental factors that restrict fetal movement.
Treatment for arthrogryposis typically involves a combination of physical therapy, bracing, and surgery to help improve joint mobility and function. The prognosis for individuals with arthrogryposis varies depending on the severity and type of contractures present, as well as the underlying cause of the condition.
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.
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.
Aplastic anemia is a medical condition characterized by pancytopenia (a decrease in all three types of blood cells: red blood cells, white blood cells, and platelets) due to the failure of bone marrow to produce new cells. It is called "aplastic" because the bone marrow becomes hypocellular or "aplastic," meaning it contains few or no blood-forming stem cells.
The condition can be acquired or inherited, with acquired aplastic anemia being more common. Acquired aplastic anemia can result from exposure to toxic chemicals, radiation, drugs, viral infections, or autoimmune disorders. Inherited forms of the disease include Fanconi anemia and dyskeratosis congenita.
Symptoms of aplastic anemia may include fatigue, weakness, shortness of breath, pale skin, easy bruising or bleeding, frequent infections, and fever. Treatment options for aplastic anemia depend on the severity of the condition and its underlying cause. They may include blood transfusions, immunosuppressive therapy, and stem cell transplantation.
Rothmund-Thomson syndrome (RTS) is a rare genetic disorder characterized by the triad of poikiloderma, juvenile cataracts, and skeletal abnormalities. Poikiloderma is a skin condition that involves changes in coloration, including redness, brownish pigmentation, and telangiectasia (dilation of small blood vessels), as well as atrophy (wasting) of the skin.
The syndrome is caused by mutations in the RECQL4 gene, which plays a role in DNA repair. RTS has an autosomal recessive pattern of inheritance, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to develop the condition.
Individuals with RTS may also experience other symptoms, such as sparse hair, short stature, small hands and feet, missing teeth, and a predisposition to developing certain types of cancer, particularly osteosarcoma (a type of bone cancer). The severity of the condition can vary widely among individuals.
RTS is typically diagnosed based on clinical features and genetic testing. Treatment is focused on managing the symptoms of the condition and may include measures such as sun protection to prevent skin damage, eye exams to monitor for cataracts, and regular cancer screenings.
Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.
Leukoplakia, oral is a predominantly white patch or plaque that cannot be characterized clinically or pathologically as any other disease. It is an oral potentially malignant disorder (OPMD) and represents a significant risk for the development of squamous cell carcinoma. The lesions are typically caused by chronic irritation, such as smoking or smokeless tobacco use, and are most commonly found on the tongue, floor of the mouth, and buccal mucosa. The diagnosis is confirmed through a biopsy, and management includes removal of causative factors and close monitoring for any signs of malignant transformation.
Cell cycle proteins are a group of regulatory proteins that control the progression of the cell cycle, which is the series of events that take place in a eukaryotic cell leading to its division and duplication. These proteins can be classified into several categories based on their functions during different stages of the cell cycle.
The major groups of cell cycle proteins include:
1. Cyclin-dependent kinases (CDKs): CDKs are serine/threonine protein kinases that regulate key transitions in the cell cycle. They require binding to a regulatory subunit called cyclin to become active. Different CDK-cyclin complexes are activated at different stages of the cell cycle.
2. Cyclins: Cyclins are a family of regulatory proteins that bind and activate CDKs. Their levels fluctuate throughout the cell cycle, with specific cyclins expressed during particular phases. For example, cyclin D is important for the G1 to S phase transition, while cyclin B is required for the G2 to M phase transition.
3. CDK inhibitors (CKIs): CKIs are regulatory proteins that bind to and inhibit CDKs, thereby preventing their activation. CKIs can be divided into two main families: the INK4 family and the Cip/Kip family. INK4 family members specifically inhibit CDK4 and CDK6, while Cip/Kip family members inhibit a broader range of CDKs.
4. Anaphase-promoting complex/cyclosome (APC/C): APC/C is an E3 ubiquitin ligase that targets specific proteins for degradation by the 26S proteasome. During the cell cycle, APC/C regulates the metaphase to anaphase transition and the exit from mitosis by targeting securin and cyclin B for degradation.
5. Other regulatory proteins: Several other proteins play crucial roles in regulating the cell cycle, such as p53, a transcription factor that responds to DNA damage and arrests the cell cycle, and the polo-like kinases (PLKs), which are involved in various aspects of mitosis.
Overall, cell cycle proteins work together to ensure the proper progression of the cell cycle, maintain genomic stability, and prevent uncontrolled cell growth, which can lead to cancer.
Keratosis, in general, refers to a skin condition characterized by the abnormal growth or development of keratin, a protein that forms part of the outer layer of the skin (epidermis). There are several types of keratosis, including:
1. Seborrheic Keratosis: benign, often pigmented, rough, and scaly growths that can appear anywhere on the body. They tend to increase in number with age.
2. Actinic Keratosis: rough, scaly patches or spots on the skin that are caused by long-term exposure to sunlight or artificial UV light. These have the potential to develop into squamous cell carcinoma, a type of skin cancer.
3. Solar Keratosis: another term for actinic keratosis, as it is primarily caused by sun damage.
4. Keratosis Pilaris: a common condition where small, rough bumps appear on the skin, often on the arms, thighs, or cheeks. These are caused by excess keratin blocking hair follicles.
5. Follicular Keratosis: a disorder characterized by the formation of horny plugs within the hair follicles, leading to rough, sandpaper-like bumps on the skin.
6. Intraepidermal Keratosis: a term used to describe the abnormal accumulation of keratin in the epidermis, which can lead to various skin conditions.
It's important to consult with a healthcare professional or dermatologist for proper diagnosis and treatment if you suspect having any form of keratosis.
Diamond-Blackfan anemia is a rare, congenital bone marrow failure disorder characterized by a decreased production of red blood cells (erythroblasts) in the bone marrow. This results in a reduced number of circulating red blood cells, leading to anemia and related symptoms such as fatigue, weakness, and pallor. The disorder is typically diagnosed in infancy or early childhood and can also be associated with physical abnormalities.
The exact cause of Diamond-Blackfan anemia is not fully understood, but it is believed to involve genetic mutations that affect the development and function of the bone marrow. In many cases, the disorder is inherited in an autosomal dominant manner, meaning that a child has a 50% chance of inheriting the mutated gene from an affected parent. However, some cases may arise spontaneously due to new genetic mutations.
Treatment for Diamond-Blackfan anemia typically involves regular blood transfusions to maintain adequate red blood cell levels and alleviate symptoms. Corticosteroid therapy may also be used to stimulate red blood cell production in some cases. In severe or refractory cases, stem cell transplantation may be considered as a curative treatment option.
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).
I'm sorry for any confusion, but "Hydro-Lyases" is not a recognized medical term or category in biochemistry. It seems like there might be a misunderstanding or a typo in the term.
In biochemistry, "lyases" are enzymes that catalyze the removal of groups from substrates by means other than hydrolysis or oxidation, often forming a double bond or a ring-forming reaction. They are classified and named based on the type of bond they break.
If you meant to ask about a specific enzyme or reaction, could you please provide more context or clarify the term? I'd be happy to help further with accurate information.
Ectodermal dysplasia (ED) is a group of genetic disorders that affect the development and formation of ectodermal tissues, which include the skin, hair, nails, teeth, and sweat glands. The condition is usually present at birth or appears in early infancy.
The symptoms of ED can vary widely depending on the specific type and severity of the disorder. Common features may include:
* Sparse or absent hair
* Thin, wrinkled, or rough skin
* Abnormal or missing teeth
* Nail abnormalities
* Absent or reduced sweat glands, leading to heat intolerance and problems regulating body temperature
* Ear abnormalities, which can result in hearing loss
* Eye abnormalities
ED is caused by mutations in genes that are involved in the development of ectodermal tissues. Most cases of ED are inherited in an autosomal dominant or autosomal recessive pattern, meaning that a child can inherit the disorder even if only one parent (dominant) or both parents (recessive) carry the mutated gene.
There is no cure for ED, but treatment is focused on managing the symptoms and improving quality of life. This may include measures to maintain body temperature, such as cooling vests or frequent cool baths; dental treatments to replace missing teeth; hearing aids for hearing loss; and skin care regimens to prevent dryness and irritation.
Skin diseases, also known as dermatological conditions, refer to any medical condition that affects the skin, which is the largest organ of the human body. These diseases can affect the skin's function, appearance, or overall health. They can be caused by various factors, including genetics, infections, allergies, environmental factors, and aging.
Skin diseases can present in many different forms, such as rashes, blisters, sores, discolorations, growths, or changes in texture. Some common examples of skin diseases include acne, eczema, psoriasis, dermatitis, fungal infections, viral infections, bacterial infections, and skin cancer.
The symptoms and severity of skin diseases can vary widely depending on the specific condition and individual factors. Some skin diseases are mild and can be treated with over-the-counter medications or topical creams, while others may require more intensive treatments such as prescription medications, light therapy, or even surgery.
It is important to seek medical attention if you experience any unusual or persistent changes in your skin, as some skin diseases can be serious or indicative of other underlying health conditions. A dermatologist is a medical doctor who specializes in the diagnosis and treatment of skin diseases.
Fanconi anemia is a rare, inherited disorder that affects the body's ability to produce healthy blood cells. It is characterized by bone marrow failure, congenital abnormalities, and an increased risk of developing certain types of cancer. The condition is caused by mutations in genes responsible for repairing damaged DNA, leading to chromosomal instability and cell death.
The classic form of Fanconi anemia (type A) is typically diagnosed in childhood and is associated with various physical abnormalities such as short stature, skin pigmentation changes, thumb and radial ray anomalies, kidney and genitourinary malformations, and developmental delays. Other types of Fanconi anemia (B-G) may have different clinical presentations but share the common feature of bone marrow failure and cancer predisposition.
Bone marrow failure in Fanconi anemia results in decreased production of all three types of blood cells: red blood cells, white blood cells, and platelets. This can lead to anemia (low red blood cell count), neutropenia (low white blood cell count), and thrombocytopenia (low platelet count). These conditions increase the risk of infections, fatigue, and bleeding.
Individuals with Fanconi anemia have a significantly higher risk of developing various types of cancer, particularly acute myeloid leukemia (AML) and solid tumors such as squamous cell carcinomas of the head, neck, esophagus, and anogenital region.
Treatment for Fanconi anemia typically involves managing symptoms related to bone marrow failure, such as transfusions, growth factors, and antibiotics. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment option for bone marrow failure but carries risks of its own, including graft-versus-host disease and transplant-related mortality. Regular cancer surveillance is essential due to the increased risk of malignancies in these patients.
DAX-1 (Dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1) is a nuclear receptor protein that functions as a transcriptional regulator. It is also known as NR0B1 (Nuclear Receptor Subfamily 0, Group B, Member 1).
DAX-1 plays crucial roles in various developmental processes, including sexual differentiation and adrenal gland development. Mutations in the DAX-1 gene have been associated with X-linked adrenal hypoplasia congenita (AHC), a condition characterized by defective adrenal gland development and primary adrenal insufficiency.
The term "Orphan Nuclear Receptor" refers to a class of nuclear receptors for which no natural ligand has been identified yet. DAX-1 is one such orphan nuclear receptor, as its specific endogenous ligand remains unknown. However, recent studies suggest that steroids and other small molecules might interact with DAX-1 and modulate its activity.
Darier Disease is a genetic skin disorder, also known as Keratosis Follicularis. It is characterized by the formation of greasy, crusted, keratotic papules and plaques that typically appear on the upper arms, torso, and scalp. The lesions may also affect the nasolabial folds, central face, and mucous membranes. Darier Disease is caused by mutations in the ATP2A2 gene, which encodes a calcium pump protein involved in keratinization. It is an autosomal dominant disorder, meaning that a person has a 50% chance of inheriting the disease if one of their parents is affected. The onset of symptoms typically occurs during adolescence or early adulthood. Treatment options include topical medications, oral retinoids, and photodynamic therapy.
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired disorder of the blood characterized by the destruction of red blood cells (hemolysis), which can cause symptoms such as fatigue, dark colored urine (especially in the morning), chest pain, shortness of breath, and an increased risk of blood clots. The hemoglobin from the lysed red blood cells appears in the urine, hence the term "hemoglobinuria."
The paroxysmal nature of the disorder refers to the sudden and recurring episodes of hemolysis that can occur at any time, although they may be more frequent at night. The condition is caused by mutations in a gene called PIG-A, which leads to the production of defective red blood cell membranes that are sensitive to destruction by complement, a component of the immune system.
PNH is a serious and potentially life-threatening condition that can lead to complications such as kidney damage, pulmonary hypertension, and thrombosis. Treatment typically involves supportive care, such as blood transfusions, and medications to manage symptoms and prevent complications. In some cases, stem cell transplantation may be considered as a curative treatment option.
The X chromosome is one of the two types of sex-determining chromosomes in humans (the other being the Y chromosome). It's one of the 23 pairs of chromosomes that make up a person's genetic material. Females typically have two copies of the X chromosome (XX), while males usually have one X and one Y chromosome (XY).
The X chromosome contains hundreds of genes that are responsible for the production of various proteins, many of which are essential for normal bodily functions. Some of the critical roles of the X chromosome include:
1. Sex Determination: The presence or absence of the Y chromosome determines whether an individual is male or female. If there is no Y chromosome, the individual will typically develop as a female.
2. Genetic Disorders: Since females have two copies of the X chromosome, they are less likely to be affected by X-linked genetic disorders than males. Males, having only one X chromosome, will express any recessive X-linked traits they inherit.
3. Dosage Compensation: To compensate for the difference in gene dosage between males and females, a process called X-inactivation occurs during female embryonic development. One of the two X chromosomes is randomly inactivated in each cell, resulting in a single functional copy per cell.
The X chromosome plays a crucial role in human genetics and development, contributing to various traits and characteristics, including sex determination and dosage compensation.
Myotonic disorders are a group of genetic muscle diseases characterized by the inability to relax muscles (myotonia) after contraction. Myotonia can cause symptoms such as stiffness, muscle spasms, and prolonged muscle contractions or cramps. These disorders may also be associated with other symptoms, including muscle weakness, wasting, and various systemic features.
The most common myotonic disorder is myotonic dystrophy type 1 (DM1), which is caused by a mutation in the DMPK gene. Myotonic dystrophy type 2 (DM2) is another form of myotonic dystrophy, resulting from a mutation in the CNBP gene. These two forms of myotonic dystrophy have distinct genetic causes but share similar clinical features, such as myotonia and muscle weakness.
Other less common myotonic disorders include:
1. Myotonia congenita - A group of inherited conditions characterized by muscle stiffness from birth or early childhood. There are two main types: Thomsen's disease (autosomal dominant) and Becker's disease (autosomal recessive).
2. Paramyotonia congenita - An autosomal dominant disorder characterized by muscle stiffness triggered by cold temperatures or physical exertion.
3. Potassium-aggravated myotonia (PAM) - A rare, autosomal dominant condition with symptoms similar to paramyotonia congenita but without the cold sensitivity.
4. Myotonia fluctuans - A rare, autosomal dominant disorder characterized by fluctuating muscle stiffness and cramps.
5. Acquired myotonia - Rare cases of myotonia caused by factors other than genetic mutations, such as medication side effects or underlying medical conditions.
Myotonic disorders can significantly impact a person's quality of life, making daily activities challenging. Proper diagnosis and management are essential to help alleviate symptoms and improve overall well-being.
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.
Keratin-6 is a specific type of keratin protein that is expressed in the epithelial tissues, including the skin and hair follicles. It is a member of the keratin family of intermediate filament proteins, which provide structural support to cells. There are several subtypes of Keratin-6 (A, B, C, and D), each with distinct functions and expression patterns.
Keratin-6A and -6B are expressed in response to injury or stress in the epithelial tissues, where they play a role in wound healing by promoting cell migration and proliferation. They have also been implicated in the development of certain skin disorders, such as psoriasis and epidermolysis bullosa simplex.
Keratin-6C is primarily expressed in the hair follicles, where it helps to regulate the growth and structure of the hair shaft. Mutations in the gene encoding Keratin-6C have been associated with certain forms of hair loss, such as monilethrix and pili torti.
Keratin-6D is also expressed in the hair follicles, where it plays a role in maintaining the integrity of the hair shaft. Mutations in the gene encoding Keratin-6D have been linked to certain forms of wooly hair and hair loss.
Keratoderma, palmoplantar is a medical term that refers to a group of skin conditions characterized by thickening and hardening (hyperkeratosis) of the skin on the palms of the hands and soles of the feet. This condition can affect people of all ages, but it's most commonly seen in children.
The thickening of the skin is caused by an overproduction of keratin, a protein that helps to form the tough, outer layer of the skin. In palmoplantar keratoderma, this excess keratin accumulates in the stratum corneum, the outermost layer of the epidermis, leading to the formation of rough, scaly, and thickened patches on the palms and soles.
There are several different types of palmoplantar keratoderma, each with its own specific symptoms and causes. Some forms of the condition are inherited and present at birth or develop in early childhood, while others may be acquired later in life as a result of an underlying medical condition, such as atopic dermatitis, lichen planus, or psoriasis.
Treatment for palmoplantar keratoderma typically involves the use of emollients and keratolytic agents to help soften and remove the thickened skin. In some cases, oral retinoids or other systemic medications may be necessary to manage more severe symptoms. It's important to consult with a healthcare provider for an accurate diagnosis and treatment plan.
Keratin-16 is a type of keratin protein that is specifically expressed in the suprabasal layers of epithelial tissues, including the skin and nails. It belongs to the family of keratins known as "hard keratins" or "intermediate filament proteins," which provide structural support and protection to these tissues.
Keratin-16 is often upregulated in response to stress, injury, or inflammation, leading to the formation of thickened, hardened epithelial structures. This can result in skin conditions such as calluses, corns, and blisters, as well as nail abnormalities like brittle or ridged nails.
In addition, keratin-16 has been implicated in various disease states, including psoriasis, eczema, and certain types of cancer. Its expression is often used as a marker for epithelial differentiation and tissue remodeling.
Keratin-1
"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.
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.
Corneal keratocytes are specialized cells located within the stroma, which is the thickest layer of the cornea, which is the clear front "window" of the eye. These cells play a crucial role in maintaining the transparency and structural integrity of the cornea. Keratocytes are star-shaped cells that produce and maintain the extracellular matrix (ECM) of the corneal stroma, which consists mainly of collagen fibrils and proteoglycans.
In a healthy cornea, keratocytes exist in a quiescent state, but they can become activated and undergo phenotypic changes in response to injury or disease. Activated keratocytes can differentiate into fibroblasts or myofibroblasts, which participate in the wound healing process by synthesizing ECM components and contracting to help close wounds. However, an overactive or dysregulated wound healing response can lead to corneal opacity, scarring, and visual impairment.
Therefore, understanding the behavior and regulation of corneal keratocytes is essential for developing effective therapies and treatments for various corneal disorders and diseases.
Dyskeratosis congenita
WRAP53
Dyskeratosis
Telomerase
Hoyeraal-Hreidarsson syndrome
Telomerase reverse transcriptase
Dyskerin
Ribosomopathy
Revesz syndrome
Bone marrow failure
Telomerase RNA component
Mosaic (genetics)
Deaths in January 2012
MAGEA10
MAGEA2
MAGEA11
MAGEA4
Melanoma antigen family a, 8
Y RNA
MAGEA1
Poly(A)-specific ribonuclease
MAGEA9
MAGEA3
MAGEA5
MAGEA12
Telomeric repeat-containing RNA
Anticipation (genetics)
TINF2
Cerebroretinal microangiopathy with calcifications and cysts
Leukoplakia
Dyskeratosis congenita - Wikipedia
Dyskeratosis congenita: MedlinePlus Genetics
Dyskeratosis Congenita: Background, Pathophysiology, Etiology
Dyskeratosis Congenita | Boston Children's Hospital
Telomere shortening and loss of self-renewal in dyskeratosis congenita induced pluripotent stem cells
Pulmonary fibrosis in dyskeratosis congenita with TINF2 gene mutation | European Respiratory Society
Dyskeratosis Congenita: Background, Pathophysiology, Etiology
Scientists discover genetic cause of deadly rare disease 'dyskeratosis congenita'
Dyskeratosis congenita: clinical features and genetic aspects. Report of a family and review of the literature. | Journal of...
Dyskeratosis congenita
Dyskeratosis Congenita Differential Diagnoses
Dyskeratosis Congenita: Background, Pathophysiology, Epidemiology
Dyskeratosis Congenita | Boston Children's Hospital
Dyskeratosis Congenita | City Life Toronto Lifestyle Magazine
Congenital Abnormalities - Dyskeratosis Congenita | CU Experts | CU Boulder
Fact file for Hoyeraal-Hreidarsson syndrome/Dyskeratosis congenita
machineLearning iconDark - DC Action: Dyskeratosis Congenita Advocacy / Education / Support
Figure 1. [Examples of the dyskeratosis congenita diagnostic triad]. - GeneReviews® - NCBI Bookshelf
JCI - Welcome
Fanconi anaemia | The Aplastic Anaemia Trust
The 2017 IUIS Phenotypic Classification for Primary Immunodeficiencies | Journal of Clinical Immunology
The genomic landscape of pediatric myelodysplastic syndromes | Nature Communications
Neutropenia: Practice Essentials, Background, Pathophysiology
Coriell Institute for Medical Research
TERT telomerase reverse transcriptase [Homo sapiens (human)] - Gene - NCBI
Germline NPM1 mutations lead to altered rRNA 2′-O-methylation and cause dyskeratosis congenita<...
Telomere diseases
Rondeep Brar | Stanford Medicine
TERC telomerase RNA component [Homo sapiens (human)] - Gene - NCBI
Mutations20
- The best characterized form of dyskeratosis congenita is a result of one or more mutations in the long arm of the X chromosome in the gene DKC1. (wikipedia.org)
- In about half of people with dyskeratosis congenita, the disorder is caused by mutations in the TERT , TERC , DKC1 , or TINF2 gene. (medlineplus.gov)
- In a small number of individuals with dyskeratosis congenita, mutations in other genes involved with telomere maintenance have been identified. (medlineplus.gov)
- Other affected individuals have no mutations in any of the genes currently associated with dyskeratosis congenita. (medlineplus.gov)
- Dyskeratosis congenita is characterized by defective maintenance of blood, pulmonary tissue and epidermal tissues and is caused by mutations in genes controlling telomere homeostasis. (nih.gov)
- In iPSCs from a form of dyskeratosis congenita caused by mutations in TCAB1 (also known as WRAP53), telomerase catalytic activity is unperturbed, yet the ability of telomerase to lengthen telomeres is abrogated, because telomerase mislocalizes from Cajal bodies to nucleoli within the iPSCs. (nih.gov)
- Eight dyskeratosis congenita genes ( DKC1 (dyskeratosis congenita 1), TERC (telomerase RNA component), TERT (telomerase reverse transcriptase), NOP10 (nucleolar protein 10), NHP2 , TINF2 (TERF1-interacting nuclear factor 2), TCAB1 and RTEL1 (regulation of telomere elongation helicase 1)) have already been identified, and their mutations account for ∼60% of all dyskeratosis congenita cases [ 1 ]. (ersjournals.com)
- Among the dyskeratosis congenita genes, mutations in TERC , TERT and DKC1 have recently been reported to be associated with familial pulmonary fibrosis and idiopathic pulmonary fibrosis, and pulmonary fibrosis is recognised as one of the features of dyskeratosis congenita. (ersjournals.com)
- However, the relationship between mutations in the other dyskeratosis congenita genes and pulmonary fibrosis has not yet been clarified. (ersjournals.com)
- Brault ME, Lauzon C, Autexier C. Dyskeratosis congenita mutations in dyskerin SUMOylation consensus sites lead to impaired telomerase RNA accumulation and telomere defects. (medscape.com)
- Telomerase reverse-transcriptase homozygous mutations in autosomal recessive dyskeratosis congenita and Hoyeraal-Hreidarsson syndrome. (medscape.com)
- Genetic heterogeneity in autosomal recessive dyskeratosis congenita with one subtype due to mutations in the telomerase-associated protein NOP10. (medscape.com)
- CTC1 Mutations in a patient with dyskeratosis congenita. (medscape.com)
- In this episode, Tom Vulliamy and Hemanth Tummala discuss their work, which identifies biallelic mutations in the gene encoding poly(A)-specific ribonuclease ( PARN ) in three families with severe dyskeratosis congenita. (jci.org)
- We identify NPM1 germline mutations in patients with dyskeratosis congenita presenting with bone marrow failure and demonstrate that they are deficient in small nucleolar RNA binding. (elsevierpure.com)
- Mutations in this gene cause autosomal dominant dyskeratosis congenita, and may also be associated with some cases of aplastic anemia. (nih.gov)
- Telomerase mutations cause autosomal dominant dyskeratosis congenita. (hopkinsmedicine.org)
- Mutations in the telomerase accessory component, DKC1 , the dyskeratosis congenita 1 gene, can also manifest as IPF, underscoring the important role of telomere dysfunction in IPF pathogenesis [ 10 ]. (ersjournals.com)
- Loss of function mutations of human DKC1 gene cause Dyskeratosis Congenita X-linked (X-DC), a multisystemic syndrome accompanied by telomerase defects, premature aging, increased cancer susceptibility and stem cell dysfunction. (unina.it)
- Moreover, mutations in telomerase genes have been associated with a multitude of diseases including aplastic anaemia, dyskeratosis congenita, and idiopathic pulmonary fibrosis. (asu.edu)
Telomeres5
- Short telomeres, a hallmark of dyskeratosis congenita, impair tissue stem cell function in mouse models, indicating that a tissue stem cell defect may underlie the pathophysiology of dyskeratosis congenita. (nih.gov)
- Dysfunctional telomeres and dyskeratosis congenita. (medscape.com)
- Touzot F, Le Guen T, de Villartay JP, Revy P. Dyskeratosis congenita: short telomeres are not the rule. (medscape.com)
- Review Short telomeres: from dyskeratosis congenita to sporadic aplastic anemia and malignancy. (nih.gov)
- The inherited disorder dyskeratosis congenita is characterized by short telomeres, mucocutaneous abnormalities, and bone marrow failure. (jci.org)
Patient with dyskeratosis congenita1
- Pulmonary involvement in a patient with dyskeratosis congenita. (uludag.edu.tr)
DKC13
- In contrast, mutation of dyskerin (DKC1) in X-linked dyskeratosis congenita severely impairs telomerase activity by blocking telomerase assembly and disrupts telomere elongation during reprogramming. (nih.gov)
- Extended culture of DKC1-mutant iPSCs leads to progressive telomere shortening and eventual loss of self-renewal, indicating that a similar process occurs in tissue stem cells in dyskeratosis congenita patients. (nih.gov)
- Defects in DKC1 are a cause of X-linked dyskeratosis congenita (DKC) and Hoyeraal-Hreidarsson syndrome (HHS). (lu.se)
Recessive1
- This study in our family indicates absence of close linkage between the Xga locus and the X-linked recessive form of dyskeratosis congenita. (bmj.com)
Disorder5
- Dyskeratosis congenita (DKC), also known as Zinsser-Engman-Cole syndrome, is a rare progressive congenital disorder with a highly variable phenotype. (wikipedia.org)
- Myelodysplastic Syndrome is associated with this syndrome usually presenting as a Hypoplastic Bone Marrow that can resemble Aplastic Anemia, but can be differentiated with >10% dysplasia in affected cell lines, sometimes not possible though because of the Hypoplastic marrow reducing blood cells to be observed, genetic clones are usually not present more often than not with Hypoplastic Myelodysplastic Disorder associated with Dyskeratosis Congenita. (wikipedia.org)
- Dyskeratosis congenita is a disorder that can affect many parts of the body. (medlineplus.gov)
- Dyskeratosis congenita is a rare inherited disorder of ectodermal dysplasia characterised by the classical mucocutaneous triad of abnormal skin pigmentation, nail dystrophy and leukoplakia [ 1 - 3 ], at least one of which is present in around 80-90% of dyskeratosis congenita cases. (ersjournals.com)
- Walne AJ, Marrone A, Dokal I. Dyskeratosis congenita: a disorder of defective telomere maintenance? (medscape.com)
Aplastic anaemia1
- Dyskeratosis congenita is an inherited type of aplastic anaemia causing premature ageing due to telomere repair abnormalities. (theaat.org.uk)
Mutation2
- To the best of our knowledge, this is the first case report describing a dyskeratosis congenita patient with pulmonary fibrosis who had a TINF2 mutation. (ersjournals.com)
- Mice harboring a dyskeratosis congenita germline Npm1 mutation recapitulate both hematological and nonhematological features of dyskeratosis congenita. (elsevierpure.com)
Fanconi's1
- The parallel is made between dyskeratosis congenita and Fanconi's anaemia. (bmj.com)
Pulmonary fibrosis2
- People with dyskeratosis congenita may also develop pulmonary fibrosis, a condition that causes scar tissue (fibrosis) to build up in the lungs, decreasing the transport of oxygen into the bloodstream. (medlineplus.gov)
- Pulmonary fibrosis in dyskeratosis congenita: a case report with a PRISMA-compliant systematic review. (nih.gov)
Telomere maintenance3
- Here we show that even in the undifferentiated state, iPSCs from dyskeratosis congenita patients harbour the precise biochemical defects characteristic of each form of the disease and that the magnitude of the telomere maintenance defect in iPSCs correlates with clinical severity. (nih.gov)
- Mason PJ, Wilson DB, Bessler M. Dyskeratosis congenita -- a disease of dysfunctional telomere maintenance. (medscape.com)
- The accumulation and not the specific activity of telomerase ribonucleoprotein determines telomere maintenance deficiency in X-linked dyskeratosis congenita. (medscape.com)
Bone3
- The main causes of mortality in dyskeratosis congenita are bone marrow failure, pulmonary disease and malignancy [ 1 ]. (ersjournals.com)
- Dyskeratosis congenita (DKC), also known as Zinsser-Engman-Cole syndrome, is a rare, progressive bone marrow failure syndrome characterized by the triad of reticulated skin hyperpigmentation, nail dystrophy, and oral leukoplakia. (medscape.com)
- Dyskeratosis congenita (DC) and related syndromes are inherited, life-threatening bone marrow (BM) failure disorders, and approximately 40% of cases are currently uncharacterized at the genetic level. (jci.org)
Syndrome2
- People with dyskeratosis congenita are also at increased risk of developing leukemia even if they never develop myelodysplastic syndrome. (medlineplus.gov)
- Dyskeratosis congenita (DKC), also known as Zinsser-Engman-Cole syndrome, was first described in 1906. (medscape.com)
Patients3
- These findings in iPSCs from dyskeratosis congenita patients reveal that undifferentiated iPSCs accurately recapitulate features of a human stem cell disease and may serve as a cell-culture-based system for the development of targeted therapeutics. (nih.gov)
- Haematological recovery in dyskeratosis congenita patients treated with danazol. (medscape.com)
- Heterogeneous telomere defects in patients with severe forms of dyskeratosis congenita. (medscape.com)
Severely1
- While most people with dyskeratosis congenita have normal intelligence and development of motor skills such as standing and walking, developmental delay may occur in some severely affected individuals. (medlineplus.gov)
Findings1
- These findings will be extremely useful as we embark on future research to increase our understanding of the molecular mechanisms relating to dyskeratosis congenita. (medicalxpress.com)
Severity2
- The severity of dyskeratosis congenita varies widely among affected individuals. (medlineplus.gov)
- Telomere length is associated with disease severity and declines with age in dyskeratosis congenita. (medscape.com)
Clinical2
- Dyskeratosis congenita: clinical features and genetic aspects. (bmj.com)
- Dyskeratosis congenita: a combined immunodeficiency with broad clinical spectrum--a single-center pediatric experience. (medscape.com)
Symptoms4
- in addition to the other symptoms of dyskeratosis congenita. (medlineplus.gov)
- What are the symptoms of dyskeratosis congenita? (childrenshospital.org)
- Dyskeratosis congenita (DC) symptoms and the onset of symptoms vary among those affected. (childrenshospital.org)
- Because people have different symptoms at different points in their lives, it is often difficult for doctors to diagnose dyskeratosis congenita (DC). (childrenshospital.org)
Mice1
- Dyskeratosis congenita and cancer in mice deficient in ribosomal RNA modification. (medscape.com)
Form1
- The results of this study establish a causative role for PARN in a severe form of dyskeratosis congenita. (jci.org)
Diagnose1
- Dyskeratosis congenita is extremely rare and difficult to diagnose. (medicalxpress.com)
Diseases2
- Dyskeratosis congenita (DC) is a rare condition classified under a broad spectrum of genetic disorders known as telomere diseases. (childrenshospital.org)
- In dyskeratosis congenita and other telomere diseases, the protective caps on people's chromosomes shorten too quickly, causing cells and tissues to age prematurely. (childrenshospital.org)
People1
- People with dyskeratosis congenita have an increased risk of developing several life-threatening conditions. (medlineplus.gov)
Relationship1
- The Relationship between DNA Methylation and Telomere Length in Dyskeratosis Congenita. (medscape.com)
Treatment1
- A 4.5-year-old boy with dyskeratosis congenita was brought for treatment to our hospital due to severe persistent cytopenia. (cdc.gov)
Common1
- Common variable immunodeficiency as the initial presentation of dyskeratosis congenita. (medscape.com)