A mitochondrial encephalomyopathy characterized clinically by a mixed seizure disorder, myoclonus, progressive ataxia, spasticity, and a mild myopathy. Dysarthria, optic atrophy, growth retardation, deafness, and dementia may also occur. This condition tends to present in childhood and to be transmitted via maternal lineage. Muscle biopsies reveal ragged-red fibers and respiratory chain enzymatic defects. (From Adams et al., Principles of Neurology, 6th ed, p986)
A condition characterized by the growth of unencapsulated masses of ADIPOSE TISSUE symmetrically deposited around the neck, shoulders, or other sites around the body.
A characteristic symptom complex.
A mitochondrial disorder characterized by focal or generalized seizures, episodes of transient or persistent neurologic dysfunction resembling strokes, and ragged-red fibers on muscle biopsy. Affected individuals tend to be normal at birth through early childhood, then experience growth failure, episodic vomiting, and recurrent cerebral insults resulting in visual loss and hemiparesis. The cortical lesions tend to occur in the parietal and occipital lobes and are not associated with vascular occlusion. VASCULAR HEADACHE is frequently associated and the disorder tends to be familial. (From Joynt, Clinical Neurology, 1992, Ch56, p117)
A transfer RNA which is specific for carrying lysine to sites on the ribosomes in preparation for protein synthesis.
A clinically diverse group of epilepsy syndromes characterized either by myoclonic seizures or by myoclonus in association with other seizure types. Myoclonic epilepsy syndromes are divided into three subtypes based on etiology: familial, cryptogenic, and symptomatic (i.e., occurring secondary to known disease processes such as infections, hypoxic-ischemic injuries, trauma, etc.).
A heterogenous group of disorders characterized by alterations of mitochondrial metabolism that result in muscle and nervous system dysfunction. These are often multisystemic and vary considerably in age at onset (usually in the first or second decade of life), distribution of affected muscles, severity, and course. (From Adams et al., Principles of Neurology, 6th ed, pp984-5)
A transfer RNA which is specific for carrying leucine to sites on the ribosomes in preparation for protein synthesis.
A mitochondrial disorder featuring the triad of chronic progressive EXTERNAL OPHTHALMOPLEGIA, cardiomyopathy (CARDIOMYOPATHIES) with conduction block (HEART BLOCK), and RETINITIS PIGMENTOSA. Disease onset is in the first or second decade. Elevated CSF protein, sensorineural deafness, seizures, and pyramidal signs may also be present. Ragged-red fibers are found on muscle biopsy. (Adams et al., Principles of Neurology, 6th ed, p984)

A novel system for assigning the mode of inheritance in mitochondrial disorders using cybrids and rhodamine 6G. (1/51)

When normal human cultured skin fibroblasts were treated with the fluorescent dye rhodamine 6G (R6G), there was a drastic reduction in numbers of intact mitochondria and electron transport chain enzyme activities, despite the fact that mitochondrial DNA (mtDNA) was still present in treated cells. We used this observation to develop a novel system for generating cybrids. When cultured skin fibroblast cells from a patient with the mitochondrial encephalopathy and ragged-red fibers (MERRF) syndrome harboring the A8344G mtDNA mutation and which showed a severe reduction in cytochrome c oxidase activity were treated with R6G and fused to enucleated HeLaCOT cells, the resulting cybrid clones showed recovery of cytochrome c oxidase activity, and were shown to have mtDNA derived solely from the HeLaCOT cell line. R6G has significant advantages over ethidium bromide in removing the mitochondrial elements from cultured cells, and the results reported here demonstrate that this strategy can be used to determine the origin of the genetic defect in patients with electron transport chain abnormalities.  (+info)

Defective kinetics of cytochrome c oxidase and alteration of mitochondrial membrane potential in fibroblasts and cytoplasmic hybrid cells with the mutation for myoclonus epilepsy with ragged-red fibres ('MERRF') at position 8344 nt. (2/51)

We have investigated pathogenic effects of the tRNA(Lys) A8344G mutation associated with the syndrome myoclonus epilepsy with ragged-red fibres (MERRF) by using fibroblasts and fibroblast-derived cytoplasmic hybrid cells harbouring different percentages of mutated mitochondrial DNA (mtDNA). The activity of cytochrome c oxidase (COX) in patient fibroblasts with 89% mutated mtDNA was decreased to 20% of the control levels. COX exhibited altered kinetics, with a decreased V(max) for both the low-affinity and high-affinity phases; however, the K(m) values were not significantly changed. The substrate-dependent synthesis of ATP was decreased to 50% of the control. Analysis of the mitochondrial membrane potential, DeltaPsi, in digitonin-treated cells with tetramethylrhodamine methyl ester (TMRM) with the use of flow cytometry showed a 80% decrease in DeltaPsi at state 4 and an increased sensitivity of DeltaPsi to an uncoupler in fibroblasts from the patient. The investigation of transmitochondrial cytoplasmic hybrid clones derived from the patient's fibroblasts enabled us to characterize the relationship between heteroplasmy of the MERRF mutation, COX activity and DeltaPsi. Within the range of 87-73% mutated mtDNA, COX activity was decreased to 5-35% and DeltaPsi was decreased to 6-78%. These results demonstrate that the MERRF mutation affects COX activity and DeltaPsi in different proportions with regard to mutation heteroplasmy and indicate that the biochemical manifestation of the MERRF mutation exerts a very steep threshold of DeltaPsi inhibition.  (+info)

Apoptosis in mitochondrial encephalomyopathies with mitochondrial DNA mutations: a potential pathogenic mechanism. (3/51)

Mitochondrial encephalomyopathies caused by mitochondrial DNA (mtDNA) defects are a genetically and phenotypically heterogeneous group of disorders. The site, percentage and distribution of mutations do not explain the overall clinical heterogeneity that is found. Apoptosis (programmed cell death) is an evolutionarily conserved mechanism that is essential for tissue development and homeostasis. Dysregulation of apoptosis has been implicated in the pathogenesis of various human diseases, such as cancer and autoimmune and neurodegenerative disorders. Recent in vitro evidence has indicated the central role of mitochondria in the apoptotic process. We investigated the occurrence of apoptosis in muscle biopsies of 36 patients carrying different mtDNA mutations and four patients with inclusion body myositis and mitochondrial abnormalities. Apoptotic features, mainly localized in cytochrome c oxidase-negative fibres, were observed in muscle fibres of patients carrying a high percentage of single mtDNA deletions (>40%) and of tRNA point mutations (>70%). By contrast, no apoptotic changes were observed in inclusion body myositis and in patients carrying mutations of mtDNA structural genes. Our study suggests that apoptosis is not simply a means whereby cells with dysfunctional mitochondria are eliminated, but that it seems to play a role in the pathogenesis of mitochondrial disorders associated with mtDNA defects affecting mitochondrial protein synthesis. The imbalance and relative abundances of nuclear-encoded and mtDNA-encoded subunits may favour cytochrome c inactivation and release. Cytochrome c, together with respiratory chain dysfunction, could activate apoptotic pathways that, in turn, inhibit the rate of mitochondrial translation and the importation of nuclear-encoded mitochondrial protein precursors. This vicious circle may amplify the biochemical defects and tissue damage and contribute to the modulation of clinical features.  (+info)

Defect in modification at the anticodon wobble nucleotide of mitochondrial tRNA(Lys) with the MERRF encephalomyopathy pathogenic mutation. (4/51)

A mitochondrial tRNA(Lys) gene mutation at nucleotide position 8344 is responsible for the myoclonus epilepsy associated with ragged-red fibers (MERRF) subgroup of mitochondrial encephalomyopathies. Here, we show that normally modified uridine at the anticodon wobble position remains unmodified in the purified mutant tRNA(Lys). We have reported a similar modification defect at the same position in two mutant mitochondrial tRNAs(Leu)(UUR) in another subgroup, mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), indicating this defect is common in the two kinds of tRNA molecules with the respective mutations of the two major mitochondrial encephalomyopathies. We therefore suggest the defect in the anticodon is responsible, through the translational process, for the pathogenesis of mitochondrial diseases.  (+info)

Cytochrome oxidase immunohistochemistry: clues for genetic mechanisms. (5/51)

Cytochrome c oxidase (COX) is encoded by three mitochondrial and nine nuclear genes. COX deficiency is genetically heterogeneous but current diagnostic methods cannot easily distinguish between mitochondrial and nuclear defects. We hypothesized that there may be differential expression of COX subunits depending on the underlying mutation. COX subunit expression was investigated in five patients with known mtDNA mutations. Severe and selective reduction of mtDNA-encoded COX subunits I and II was consistently observed in all these patients and was restricted to COX-deficient fibres. Immunostaining of nuclear-encoded subunits COX IV and Va was normal, whilst subunit VIc, also nuclear-encoded, was decreased. Twelve of 36 additional patients with histochemically defined COX deficiency also had this pattern of staining, suggesting that they had mtDNA defects. Clinical features in this group were heterogeneous, including infantile encephalopathy, multisystem disease, cardiomyopathy and childhood-onset isolated myopathy. The remaining patients did not have the same pattern of immunostaining. Fourteen had reduced staining of all subunits, whilst 10 had normal staining of all subunits despite reduced enzyme activity. Patients with COX deficiency secondary to mtDNA mutations have a specific pattern of subunit loss, but the majority of children with COX deficiency do not have this pattern of subunit loss and are likely to have nuclear gene defects.  (+info)

Simultaneous A8344G heteroplasmy and mitochondrial DNA copy number quantification in myoclonus epilepsy and ragged-red fibers (MERRF) syndrome by a multiplex molecular beacon based real-time fluorescence PCR. (6/51)

The association of a particular mitochondrial DNA (mtDNA) mutation with different clinical phenotypes is a well-known feature of mitochondrial diseases. A simple genotype-phenotype correlation has not been found between mutation load and disease expression. Tissue and intercellular mosaicism as well as mtDNA copy number are thought to be responsible for the different clinical phenotypes. As disease expression of mitochondrial tRNA mutations is mostly in postmitotic tissues, studies to elucidate disease mechanisms need to be performed on patient material. Heteroplasmy quantitation and copy number estimation using small patient biopsy samples has not been reported before, mainly due to technical restrictions. In order to resolve this problem, we have developed a robust assay that utilizes Molecular Beacons to accurately quantify heteroplasmy levels and determine mtDNA copy number in small samples carrying the A8344G tRNA(Lys) mutation. It provides the methodological basis to investigate the role of heteroplasmy and mtDNA copy number in determining the clinical phenotypes.  (+info)

Wobble modification defect in tRNA disturbs codon-anticodon interaction in a mitochondrial disease. (7/51)

We previously showed that in mitochondrial tRNA(Lys) with an A8344G mutation responsible for myoclonus epilepsy associated with ragged-red fibers (MERRF), a subgroup of mitochondrial encephalomyopathic diseases, the normally modified wobble base (a 2-thiouridine derivative) remains unmodified. Since wobble base modifications are essential for translational efficiency and accuracy, we used mitochondrial components to estimate the translational activity in vitro of purified tRNA(Lys) carrying the mutation and found no mistranslation of non-cognate codons by the mutant tRNA, but almost complete loss of translational activity for cognate codons. This defective translation was not explained by a decline in aminoacylation or lowered affinity toward elongation factor Tu. However, when direct interaction of the codon with the mutant tRNA(Lys) defective anticodon was examined by ribosomal binding analysis, the wild-type but not the mutant tRNA(Lys) bound to an mRNA- ribosome complex. We therefore concluded that the anticodon base modification defect, which is forced by the pathogenic point mutation, disturbs codon- anticodon pairing in the mutant tRNA(Lys), leading to a severe reduction in mitochondrial translation that eventually could result in the onset of MERRF.  (+info)

Histochemical and molecular genetic study of MELAS and MERRF in Korean patients. (8/51)

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episode (MELAS) and myoclonic epilepsy and ragged-red fibers (MERRF) are rare disorders caused by point mutation of the tRNA gene of the mitochondrial genome. To understand the pathogenetic mechanism of MELAS and MERRF, we studied four patients. Serially sectioned frozen muscle specimens with a battery of histochemical stains were reviewed under light microscope and ultrastructural changes were observed under electron microscope. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed and the tRNA genes were sequenced to confirm mutations. In two patients with MELAS, strongly succinyl dehydrogenase positive blood vessels (SSVs) and many cytochrome oxidase (COX) positive ragged-red fibers (RRFs) were observed, and A3243G mutations were found from the muscle samples. In two patients with MERRF, neither SSV nor COX positive RRFs were seen and A8344G mutations were found from both muscle and blood samples. In the two MERRF families, the identical mutation was observed among family members. The failure to detect the mutation in blood samples of the MELAS suggests a low mutant load in blood cells. The histochemical methods including COX stain are useful for the confirmation and differentiation of mitochondrial diseases. Also, molecular biological study using muscle sample seems essential for the confirmation of the mtDNA mutation.  (+info)

Myoclonic Epilepsy with Ragged Red Fibers (MERRF) is a rare mitochondrial disorder, which is a group of genetic disorders that affect the energy production within cells. It is characterized by multiple symptoms including myoclonus (jerky, involuntary muscle spasms), epilepsy (recurrent seizures), ataxia (lack of coordination and balance), dementia, and weakness. The name "MERRF" comes from the characteristic finding of "ragged red fibers" in muscle biopsies when viewed under a microscope using special stains. These fibers are abnormal muscle cells containing clusters of abnormal mitochondria. MERRF is caused by mutations in the mitochondrial DNA, most commonly the A8344G point mutation in the MT-TK gene. It is typically inherited from the mother and can affect multiple organs throughout the body.

Multiple Symmetrical Lipomatosis is a rare condition characterized by the growth of multiple, symmetrical fatty tumors (lipomas) beneath the skin. These lipomas are typically slow-growing and benign, but their large number and symmetric distribution can lead to significant cosmetic concerns and, in some cases, functional impairment.

The tumors usually develop on the neck, shoulders, back, and abdomen, and they may also occur on the arms and legs. While the exact cause of Multiple Symmetrical Lipomatosis is not known, it has been associated with alcohol abuse and metabolic disorders. Treatment typically involves surgical removal of the lipomas, although this can be challenging due to their number and location. Recurrence of the tumors is also common.

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.

Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) syndrome is a rare inherited mitochondrial disorder that affects the body's energy production mechanisms. It is characterized by a combination of symptoms including recurrent headaches, vomiting, seizures, vision loss, hearing impairment, muscle weakness, and stroke-like episodes affecting primarily young adults.

The condition is caused by mutations in the mitochondrial DNA (mtDNA), most commonly the A3243G point mutation in the MT-TL1 gene. The symptoms of MELAS syndrome can vary widely among affected individuals, even within the same family, due to the complex inheritance pattern of mtDNA.

MELAS syndrome is typically diagnosed based on a combination of clinical features, laboratory tests, and genetic testing. Treatment is supportive and aimed at managing individual symptoms as they arise.

I'm happy to help! Here are the definitions for each of those terms:

1. RNA (Ribonucleic Acid): RNA is a nucleic acid that plays a crucial role in the process of gene expression. It carries genetic information from DNA to the ribosomes, where proteins are synthesized. RNA is made up of a long chain of nucleotides, just like DNA, but with some key differences in its structure and composition.
2. Transfer: In the context of biochemistry, "transfer" refers to the movement or transport of molecules from one location to another within a cell or between cells. This process is often facilitated by specific proteins or other molecular carriers.
3. Lys (Lysine): Lysine is an essential amino acid that cannot be synthesized by the human body and must be obtained through diet. It plays important roles in various biological processes, including protein synthesis, enzyme function, hormone production, and energy metabolism. In molecular biology, lysine is often used as a marker for certain types of modifications to proteins or nucleic acids.

Therefore, "RNA, Transfer, Lys" could refer to the transfer RNA (tRNA) molecule that carries a specific amino acid, such as lysine, to the ribosome during protein synthesis. The tRNA molecule recognizes a specific codon on the messenger RNA (mRNA) and brings the corresponding amino acid to the growing polypeptide chain, allowing for the translation of genetic information into a functional protein.

Myoclonic epilepsies are a group of epilepsy syndromes characterized by the presence of myoclonic seizures. A myoclonic seizure is a type of seizure that involves quick, involuntary muscle jerks or twitches. These seizures can affect one part of the body or multiple parts simultaneously and may vary in frequency and severity.

Myoclonic epilepsies can occur at any age but are more common in infancy, childhood, or adolescence. Some myoclonic epilepsy syndromes have a genetic basis, while others may be associated with brain injury, infection, or other medical conditions.

Some examples of myoclonic epilepsy syndromes include:

1. Juvenile Myoclonic Epilepsy (JME): This is the most common type of myoclonic epilepsy and typically begins in adolescence. It is characterized by myoclonic jerks, often occurring upon awakening or after a period of relaxation, as well as generalized tonic-clonic seizures.
2. Progressive Myoclonic Epilepsies (PME): These are rare inherited disorders that typically begin in childhood or adolescence and involve both myoclonic seizures and other types of seizures. PMEs often progress to include cognitive decline, movement disorders, and other neurological symptoms.
3. Lennox-Gastaut Syndrome (LGS): This is a severe form of epilepsy that typically begins in early childhood and involves multiple types of seizures, including myoclonic seizures. LGS can be difficult to treat and often results in cognitive impairment and developmental delays.
4. Myoclonic Astatic Epilepsy (MAE): Also known as Doose syndrome, MAE is a childhood epilepsy syndrome characterized by myoclonic seizures, atonic seizures (brief periods of muscle weakness or loss of tone), and other types of seizures. It often responds well to treatment with antiepileptic drugs.

The management of myoclonic epilepsies typically involves a combination of medication, lifestyle changes, and, in some cases, dietary modifications. The specific treatment plan will depend on the type of myoclonic epilepsy and its underlying cause.

Mitochondrial Encephalomyopathies are a group of genetic disorders that primarily affect the mitochondria, which are the energy-producing structures in cells. "Encephalo" refers to the brain, while "myopathy" refers to muscle disease. Therefore, Mitochondrial Encephalomyopathies are conditions that cause both neurological and muscular symptoms due to impaired mitochondrial function.

These disorders can affect any organ in the body, but they primarily impact the brain, nerves, and muscles. Symptoms may include muscle weakness, seizures, developmental delays, hearing loss, vision loss, heart problems, and lactic acidosis (a buildup of lactic acid in the blood).

Mitochondrial Encephalomyopathies can be caused by mutations in either the mitochondrial DNA or nuclear DNA. They are often inherited from the mother, as mitochondria are passed down through the maternal line. However, some cases can also result from new mutations that occur spontaneously.

Due to the complex nature of these disorders and their varying symptoms, diagnosis and treatment can be challenging. Treatment typically focuses on managing specific symptoms and may include medications, dietary changes, and physical therapy.

A transfer RNA (tRNA) molecule that carries the amino acid leucine is referred to as "tRNA-Leu." This specific tRNA molecule recognizes and binds to a codon (a sequence of three nucleotides in mRNA) during protein synthesis or translation. In this case, tRNA-Leu can recognize and pair with any of the following codons: UUA, UUG, CUU, CUC, CUA, and CUG. Once bound to the mRNA at the ribosome, leucine is added to the growing polypeptide chain through the action of aminoacyl-tRNA synthetase enzymes that catalyze the attachment of specific amino acids to their corresponding tRNAs. This ensures the accurate and efficient production of proteins based on genetic information encoded in mRNA.

Kearns-Sayre Syndrome (KSS) is a rare, progressive genetic disorder that affects the function of the mitochondria, which are the energy-producing structures in cells. It is classified as a type of mitochondrial myopathy and is typically associated with symptoms that appear before the age of 20.

The medical definition of Kearns-Sayre Syndrome includes the following criteria:
1. Onset before 20 years of age
2. Progressive external ophthalmoplegia (PEO), which is characterized by weakness and paralysis of the eye muscles, leading to drooping eyelids (ptosis) and limited eye movement
3. Retinitis pigmentosa, a degenerative condition affecting the retina that can lead to vision loss
4. A cardiac conduction defect, such as heart block
5. Ragged red fibers on muscle biopsy
6. At least one major criteria or two minor criteria must be present:
* Major criteria include cerebellar ataxia (lack of coordination), deafness, or increased protein in the cerebrospinal fluid
* Minor criteria include pigmentary retinopathy, heart block, or a high level of creatine kinase in the blood.

Kearns-Sayre Syndrome is caused by a single large-scale deletion of genes in the mitochondrial DNA and is usually sporadic, meaning it occurs randomly and is not inherited from parents. The condition can be diagnosed through genetic testing, muscle biopsy, or other clinical tests. Treatment is focused on managing symptoms and may include physical therapy, surgery for ptosis, hearing aids, and pacemakers for heart block.

MERRF+Syndrome at the U.S. National Library of Medicine Medical Subject Headings (MeSH) merrf at NIH/UW GeneTests (Articles ... The causes of MERRF syndrome are difficult to determine, but because it is a mitochondrial disorder, it can be caused by the ... 1993). "A MERRF/MELAS overlap syndrome associated with a new point mutation in the mitochondrial DNA tRNA(Lys) gene". Eur. J. ... MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. It is extremely rare, and has varying ...
"A novel mitochondrial tRNAPhe mutation causes MERRF syndrome". Neurology. 62 (11): 2119-21. doi:10.1212/01.wnl.0000127608.48406 ... The features of MERRF vary widely among affected individuals, even among members of the same family. Common symptoms include: ... Mutations in the MT-TF gene have been associated with myoclonic epilepsy with ragged-red fibers (MERRF). Myoclonic epilepsy ... MERRF), Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Juvenile myopathy, encephalopathy, ...
MELAS syndrome Examples include MELAS syndrome and MERRF syndrome. These conditions can sometimes present together. KSS is ... March 2005). "Novel mitochondrial DNA ND5 mutation in a patient with clinical features of MELAS and MERRF". Arch. Neurol. 62 (3 ...
The combination of MERRF and MELAS is called the MERRF/MELAS overlap syndrome. It has not been determined how mutations alter ... also known as MERRF syndrome. In addition to symptoms of MELAS syndrome, additional signs and symptoms may include muscle ... C in the MT-TK gene has been found with MERRF syndrome. Another family with the syndrome exhibited mutations of 3243A>G and ... "MERRF syndrome without ragged-red fibers: the need for molecular diagnosis". Biochemical and Biophysical Research ...
Another example is MERRF syndrome (or Myoclonic Epilepsy with Ragged Red Fibers). In MELAS, heteroplasmy explains the variation ...
MERRF syndrome is also known as myoclonic epilepsy with ragged-red fibers. This rare inherited disorder affects muscles cells. ... Lennox-Gastaut syndrome is often associated with intellectual deficits as well as a lack of response to anti-epileptic drugs. ... There are two syndromes and several related disorders. Juvenile myoclonic epilepsy is responsible for 7% of cases of epilepsy. ... Features of MERRF, along with myoclonus epilepsy seizures, include ataxia, peripheral neuropathy, and dementia. Lafora disease ...
Mutations in mitochondrial tRNAs can be responsible for severe diseases like the MELAS and MERRF syndromes. Mutations in ... Mutations of mitochondrial DNA can lead to a number of illnesses including exercise intolerance and Kearns-Sayre syndrome (KSS ...
... mutation in a patient with features of MERRF and Kearns-Sayre syndrome". Neuromuscular Disorders. 13 (4): 334-40. doi:10.1016/ ... GeneReviews/NCBI/NIH/UW entry on Mitochondrial DNA-Associated Leigh Syndrome and NARP GeneReviews/NCBI/NIH/UW entry on MELAS ... "LHON/MELAS overlap syndrome associated with a mitochondrial MTND1 gene mutation". European Journal of Human Genetics. 13 (5): ... "Tissue mosaicism in the skeletal muscle and sural nerve biopsies in the MELAS syndrome". Acta Neurologica Scandinavica. 99 (2 ...
The combination of MERRF and MELAS is called the MERRF/MELAS overlap syndrome, which is caused by mutations in the MT-TH gene. ... also known as MERRF syndrome. In addition to symptoms of MELAS syndrome, additional signs and symptoms may include muscle ... A specific mutation of 12147G>A in the MT-TH gene has been found to result in the MERRF/MELAS overlap syndrome. A patient with ... and the MELAS/MERRF overlap syndrome. A small number of people with symptoms of mitochondrial encephalomyopathy, lactic ...
A number of mutations within mitochondrial tRNAs have been linked to diseases such as MELAS syndrome, MERRF syndrome, and ... The deletion of the 48 copies of the C/D box snoRNA SNORD116 has been shown to be the primary cause of Prader-Willi syndrome. ... "Lack of Pwcr1/MBII-85 snoRNA is critical for neonatal lethality in Prader-Willi syndrome mouse models". Mammalian Genome. 16 (6 ...
MERRF syndrome), Lafora disease (EPM2a or EMP2b), Neuronal ceroid lipofuscinosis (NCL) and sialidosis. Progressive myoclonic ...
MERRF syndrome), Lafora disease, neuronal ceroid lipofucinosis, and sialdosis. Rasmussen's encephalitis is a symptomatic ... for instance Lennox-Gastaut syndrome. Clinical syndromes in which epilepsy is not the main feature (e.g. Angelman syndrome) ... for instance Lennox-Gastaut syndrome and West syndrome. Epilepsy syndromes are classified as per the age onset. Epilepsies with ... Lennox-Gastaut syndrome (LGS) is a rare and severe form of epilepsy. As in West syndrome, LGS result from idiopathic, ...
Includes Mitochondrial Encephalitis Lactic Acidosis Seizures (MELAS), myoclonic epilepsy and ragged red fibers (MERRF), ... and Leigh syndrome. Treatment is dependent upon diagnosis and the stage at which the diagnosis is secured. For toxic and ... maternally inherited Leigh syndrome (MILS), and mitochondrial neurograstrointestinal encephalomyopathy (MNGIE), all of which ... and still others will develop a prominent cerebellar syndrome consistent with FRDA. Even though dysfunction of the mitochondria ...
... gastrointestinal pseudo-obstruction neuropathy MERRF syndrome progressive myoclonic epilepsy "Ragged Red Fibers" are clumps of ... A male baby was born in Mexico in 2016 from a mother with Leigh syndrome using MRT. In September 2012 a public consultation was ... Charlie Gard, a British boy who had mitochondrial DNA depletion syndrome; decisions about his care were taken to various law ... Charles Darwin, a nineteenth century naturalist who suffered from a disabling illness, is speculated to have MELAS syndrome. " ...
... melas syndrome MeSH C10.228.140.163.100.540 - menkes kinky hair syndrome MeSH C10.228.140.163.100.545 - merrf syndrome MeSH ... merrf syndrome MeSH C10.228.140.490.250.650.900 - unverricht-lundborg syndrome MeSH C10.228.140.490.360 - epilepsies, partial ... melas syndrome MeSH C10.668.491.500.500.550 - merrf syndrome MeSH C10.668.491.500.700 - ophthalmoplegia, chronic progressive ... cri-du-chat syndrome MeSH C10.597.606.643.210 - de lange syndrome MeSH C10.597.606.643.220 - down syndrome MeSH C10.597.606.643 ...
MERRF syndrome, and Leber's hereditary optic neuropathy. It was first characterized under this name in 1984. A feature of these ... Arreflexic coma and MELAS syndrome]" [Arreflexic coma and MELAS syndrome]. Revista Clinica Espanola (in Spanish). 209 (7): 337- ... MELAS syndrome at NLM Genetics Home Reference Hirano M, Ricci E, Koenigsberger MR, Defendini R, Pavlakis SG, DeVivo DC, et al ... MERRF patients may also have hearing loss, visual disturbance secondary to optic atrophy, and short stature. The characteristic ...
... aminoaciduria Hyperhomocysteinemia and homocysteinuria Hyperprolinemia Lead encephalopathy Leber's disease MELAS syndrome MERRF ... Rett syndrome Sulfite oxidase deficiency Wernicke's encephalopathy Antiglutamate receptor antibodies Glutamate receptor- ... Mitochondrial abnormalities (and other inherited or acquired biochemical disorders) Neuropathic pain syndromes (e.g. causalgia ...
Unverricht-Lundborg disease (Baltic myoclonus) Myoclonus epilepsy and ragged red fibres (MERRF syndrome) Lafora disease ... In MERRF bacterial proteins have been identified in treatment in mitochondrial diseases but further studies are needed. The ... While Action myoclonus renal failure (AMRF) syndrome can only be diagnosed using genetic test. Using EEG's as a form of ... In ULD EEGs show generalized epileptiform discharges and in MERRF patients show background slowing. Therefore, diagnosis is ...
MELAS syndrome MeSH C18.452.100.100.540 - Menkes kinky hair syndrome MeSH C18.452.100.100.545 - MERRF syndrome MeSH C18.452. ... MELAS syndrome MeSH C18.452.648.151.450 - menkes kinky hair syndrome MeSH C18.452.648.151.505 - MERRF syndrome MeSH C18.452. ... MELAS syndrome MeSH C18.452.660.560.620.530 - MERRF syndrome MeSH C18.452.660.560.700 - ophthalmoplegia, chronic progressive ... Li-Fraumeni syndrome MeSH C18.452.284.600 - Nijmegen breakage syndrome MeSH C18.452.284.760 - Rothmund-Thomson syndrome MeSH ...
... whereas other diseases such as MELAS syndrome, Leber's hereditary optic neuropathy, MERRF syndrome, and others are due to point ... Diseases such as Kearns-Sayre syndrome, Pearson syndrome, and progressive external ophthalmoplegia are thought to be due to ... Diseases caused by mutation in the mtDNA include Kearns-Sayre syndrome, MELAS syndrome and Leber's hereditary optic neuropathy ... chronic fatigue syndrome, retinitis pigmentosa, and diabetes mellitus. Mitochondria-mediated oxidative stress plays a role in ...
... syndrome Menkes disease MERRF syndrome Metabolic syndrome Michelin tire baby syndrome Michels Caskey syndrome Michels syndrome ... syndrome Wende-Bauckus syndrome Werner syndrome Wernicke-Korsakoff syndrome West syndrome Westerhof syndrome Wet lung syndrome ... syndrome Shone's syndrome Short anagen syndrome Short bowel syndrome short limb syndrome Short man syndrome Short QT syndrome ... syndrome Radial tunnel syndrome Rage syndrome Raghib syndrome Raine syndrome Ramos-Arroyo syndrome Ramsay Hunt syndrome type 1 ...
Those with MT-ND5 mutations can display the major features of MELAS and MERRF in some patients, as well as symptoms of Leigh's ... as well as some symptoms of Leigh's syndrome and Leber's hereditary optic neuropathy (LHON). MT-ND5 is located in mitochondrial ... "Novel mitochondrial DNA ND5 mutation in a patient with clinical features of MELAS and MERRF". Archives of Neurology. 62 (3): ... syndrome and/or Leber's hereditary optic neuropathy (LHON) in others. MT-ND5 interacts with Glutamine synthetase (GLUL), LIG4 ...
MELAS syndrome MeSH C05.651.460.620.530 - MERRF syndrome MeSH C05.651.460.700 - ophthalmoplegia, chronic progressive external ... Klippel-Feil syndrome MeSH C05.116.099.370.652 - orofaciodigital syndromes MeSH C05.116.099.370.797 - Rubinstein-Taybi syndrome ... Hajdu-Cheney syndrome MeSH C05.116.099.105 - basal-cell nevus syndrome MeSH C05.116.099.343 - dwarfism MeSH C05.116.099.343.110 ... Felty's syndrome MeSH C05.550.114.154.683 - rheumatoid nodule MeSH C05.550.114.154.774 - Sjögren syndrome MeSH C05.550.114.154. ...
Congenital myasthenic syndrome Lambert-Eaton myasthenic syndrome Isaac's syndrome Multiple sclerosis Stiff-person syndrome ... MERRF) Cytochrome c oxidase (COX) deficiency Mitochondrial complex I deficiency Mitochondrial complex II deficiency ... Mobius syndrome, cardiofacial syndrome) glossopharyngeal nerve glossopharyngeal neuralgia glomus jugulare tumor vagus nerve ... Guillain-Barré syndrome Charcot-Marie-Tooth disease Chemotherapy-induced peripheral neuropathy Median neuropathy at wrist ( ...
MERRF) Progressive myoclonic epilepsy Clumps of diseased mitochondria accumulate in muscle fibers and appear as "ragged-red ... and stroke-like syndrome (MELAS) Varying degrees of cognitive impairment and dementia Lactic acidosis Strokes Transient ... fibers" when muscle is stained with modified Gömöri trichrome stain Short stature Kearns-Sayre syndrome (KSS) External ...
Lance JW (1986). "Action myoclonus, Ramsay Hunt syndrome, and other cerebellar myoclonic syndromes". Adv Neurol. 43: 33-55. ... It is also found in MERRF (Myoclonic Epilepsy with Ragged Red Fibers), a rare mitochondrial encephalomyopathy. Jerks of muscle ... Periodic limb movement disorder Benign fasciculation syndrome Restless legs syndrome Fasciculation Brain Zaps (SSRI withdrawal ... Lennox-Gastaut syndrome (LGS), or childhood epileptic encephalopathy, is a rare epileptic disorder accounting for 1-4% of ...
MERRF syndrome) Myoclonic progressive familial epilepsy Myoclonus ataxia Myoclonus cerebellar ataxia deafness Myoclonus ... syndrome Marfan Syndrome type II Marfan Syndrome type III Marfan Syndrome type IV Marfan Syndrome type V Marfan-like syndrome, ... Mixed sclerosing bone dystrophy MLS syndrome MMEP syndrome MMT syndrome MN1 MNGIE syndrome Möbius syndrome MODY syndrome Möbius ... syndrome Mibies syndrome Michelin tire baby syndrome Michels Caskey syndrome Michels syndrome Mickleson syndrome Micrencephaly ...
MELAS syndrome MeSH C16.320.565.150.540 - Menkes kinky hair syndrome MeSH C16.320.565.150.545 - MERRF syndrome MeSH C16.320. ... MeSH C16.131.077.065 - Alagille syndrome MeSH C16.131.077.095 - Angelman syndrome MeSH C16.131.077.112 - Bardet-Biedl syndrome ... branchio-oto-renal syndrome MeSH C16.131.260.190 - cri du chat syndrome MeSH C16.131.260.210 - De Lange syndrome MeSH C16.131. ... branchio-oto-renal syndrome MeSH C16.320.180.190 - cri du chat syndrome MeSH C16.320.180.210 - De Lange syndrome MeSH C16.320. ...
MERRF syndrome) Neuropathy, ataxia, and retinitis pigmentosa (NARP syndrome) 277.88 Tumor lysis syndrome 277.89 Other specified ... Gilbert's syndrome 277.5 Mucopolysaccharidosis Hunter syndrome Hurler syndrome Morquio-Brailsford disease Sanfilippo syndrome ... with predominant t-cell defect unspecified 279.11 DiGeorge syndrome 279.12 Wiskott-Aldrich syndrome 279.13 Nezelof syndrome ... MELAS syndrome) Mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE) Myoclonus with epilepsy and with ragged red ...
MERRF+Syndrome at the U.S. National Library of Medicine Medical Subject Headings (MeSH) merrf at NIH/UW GeneTests (Articles ... The causes of MERRF syndrome are difficult to determine, but because it is a mitochondrial disorder, it can be caused by the ... 1993). "A MERRF/MELAS overlap syndrome associated with a new point mutation in the mitochondrial DNA tRNA(Lys) gene". Eur. J. ... MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. It is extremely rare, and has varying ...
MERRF) is a disorder that affects many parts of the body, particularly the muscles and nervous system. Explore symptoms, ... and MERRF syndrome. Case report. Mov Disord. 2008 Jun 15;23(8):1191-2. doi: 10.1002/mds.21990. No abstract available. Citation ... MERRF is a rare condition; its prevalence is unknown. MERRF is part of a group of conditions known as mitochondrial disorders, ... MERRF syndrome without ragged-red fibers: the need for molecular diagnosis. Biochem Biophys Res Commun. 2007 Mar 23;354(4):1058 ...
MERRF Syndrome / blood * MERRF Syndrome / diagnosis * MERRF Syndrome / enzymology * MERRF Syndrome / physiopathology* ...
... syndrome is a progressive neurodegenerative disorder. Patients may present sporadically or as members of maternal pedigrees ... Liu K, Zhao H, Ji K, Yan C. MERRF/MELAS overlap syndrome due to the m.3291T,C mutation. Metab Brain Dis. 2014 Mar. 29(1):139-44 ... long QT syndrome, or Wolff-Parkinson-White syndrome. Subjects with MELAS syndrome were found to have increased ascending aortic ... Aortic root dissection was found in one patient with MELAS syndrome. [7] Some patients may develop Leigh syndrome (ie, subacute ...
R350 MERRF syndrome - m.8344A>G *R351 NARP syndrome or maternally inherited Leigh syndrome - m.8993T>C/G ...
MtDNA mutation in MERRF syndrome causes defective aminoacylation of tRNA(Lys) and premature translation termination. Nat Genet ... steroid resistant nephrotic syndrome, and/or cystic renal disease (7). One important mitochondrial genetic cause is the m.3243A ...
Another unique moment, involved Dalia Flagert, a young girl with MERRF syndrome, a rare degenerative mitochondrial disorder ...
MERRF], Kearns-Sayre syndrome [KSS], and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS]). ... In MERRF, only one of four patients showed an increase in the lactate/creatine resonance intensity ratio (an index of ... Yet another pattern of regional metabolic abnormality was present in the MELAS syndrome, where proton spectroscopic imaging ... The regional brain metabolic abnormalities in patients with these syndromes showed different features consistent with the ...
MERRF Syndrome * Rasmussen Syndrome Epilepsy Guide. Epilepsy is often described as an electrical storm in the brain -- and the ...
Label: Unverricht-Lundborg syndrome Synonyms: Unverricht-Lundborg syndrome Alternative IDs: als API: GO ...
See also Approach to the Patient... read more (MERRF) syndrome. Progressive myoclonus and seizures, dementia, ataxia, and ... Kearns-Sayre syndrome Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia (CPEO) Impairment of oxidative ... Myoclonic epilepsy with ragged-red fibers Myoclonic epilepsy with ragged-red fibers (MERRF) Impairment of oxidative ... Chronic progressive external ophthalmoplegia Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia (CPEO) ...
MERRF is a progressive multi-system syndrome presenting in childhood or in adulthood. The rate of progression varies widely. ... Most cases of MERRF are maternally inherited due to mtDNA mutations. The most common MERRF mutation is A8344G, which accounted ... The prognosis for MERRF varies widely depending on age of onset, type and severity of symptoms, organs involved, and other ... As with all mitochondrial disorders, there is no cure for MERRF. Therapies may include coenzyme Q10, L-carnitine, and various ...
MERRF Syndrome Pharmacology, Toxicology and Pharmaceutical Science 62% * Epilepsy Medicine and Dentistry 37% ... "the MERRF mutation"). Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ... the MERRF mutation{"}). Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ... "the MERRF mutation"). Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ...
MT-TH gene mutations that cause MELAS and MERRF/MELAS overlap syndrome change single DNA building blocks (nucleotides) in the ... This combination of signs and symptoms is called MERRF/MELAS overlap syndrome. ... MERRF) and MELAS. The mutation involved in this overlap syndrome replaces the nucleotide guanine with the nucleotide adenine at ... changes alter energy production in mitochondria or cause the varied signs and symptoms of MELAS or MERRF/MELAS overlap syndrome ...
MERRF syndrome) Neuropathy, Ataxia and Retinitis Pigmentosa (NARP syndrome) Use additional code for associated conditions ... DiGeorges syndrome Pharyngeal pouch syndrome Thymic hypoplasia 279.12 Wiskott-Aldrich syndrome 279.13 Nezelofs syndrome ... Conns syndrome (255.12) 255.12 Conns syndrome 255.13 Bartters syndrome 255.14 Other secondary aldosteronism 255.2 ... 277.5 Mucopolysaccharidosis Gargoylism Hunters syndrome Hurlers syndrome Lipochondrodystrophy Maroteaux-Lamy syndrome Morquio ...
Since both MELAS and MERRF syndrome are multisystem diseases, potentially affecting liver and frequently the muscle (Ban, S. et ... MERRF) syndrome due to the variant m.8344A,G (Norose, T. et al., 2020). Patient-1 required insulin, whereas patient-2 did not ... Severity of Diabetes in MELAS and MERRF May Rather Reflect Genotype and Comorbidities than Histology of Islet Cells ... First, MELAS and MERRF are completely different disorders, why simply the genotype can explain the difference between the two ...
... and stroke-like syndrome (MELAS) and insulin-like episodes; myoclonic epilepsy and ragged-red fibers (MERRF) syndrome, and ... MERRF syndrome without ragged-red fibers: the need for molecular diagnosis. Biochem Biophys Res Commun 2007;354:1058-60.,/p,,p, ... A novel mitochondrial tRNA(Leu(UUR)) mutation in a patient with features of MERRF and Kearns-Sayre syndrome. Neuromuscul Disord ... MELAS overlap syndrome and A3243G mtDNA mutation. J Neurol Sci 1998;157(2):206-13.,/p,,p,Olson W., Engel W., Walsh G. et al. ...
... syndrome is a progressive neurodegenerative disorder. Patients may present sporadically or as members of maternal pedigrees ... Liu K, Zhao H, Ji K, Yan C. MERRF/MELAS overlap syndrome due to the m.3291T,C mutation. Metab Brain Dis. 2014 Mar. 29(1):139-44 ... May be beneficial for treatment/prevention of strokelike episodes in MELAS syndrome. The strokelike episodes in MELAS syndrome ... Creatine supplementation may increase muscle power in patients with MELAS syndrome (observed in one patient with MELAS syndrome ...
... encompasses a group of challenging epilepsy syndromes. As a group, SGE has 3 main features: (1) multiple seizure types, ... MERRF), neuronal ceroid lipofuscinoses (Batten disease), and sialidoses (cherry-red spot myoclonus syndrome). ... In Ohtahara syndrome, tonic spasms are the dominant seizure type, with little to no myoclonic seizures. [7, 8] As the brain ... West syndrome. This consists of the characteristic triad of infantile spasms, mental retardation, and an EEG pattern of ...
She is a full-time working parent of three fabulous kids from Guatemala, one of whom who has MERRF Syndrome. Her memoir, ...
Leigh syndrome, MERRF syndrome, Juvenile myopathy, encephalopathy, lactic acidosis AND stroke, NARP syndrome. not provided. no ... Rafiq syndrome, Leigh syndrome, Tuberous sclerosis 1, Developmental and epileptic encephalopathy, 14, Autosomal dominant ... not provided, Leigh syndrome. Uncertain significance. (Mar 5, 2022). criteria provided, multiple submitters, no conflicts. ... Juvenile myopathy, encephalopathy, lactic acidosis AND stroke, Leber optic atrophy, Leigh syndrome. Likely pathogenic. (Oct 31 ...
MERRF syndrome is caused by mutations in mitochondrial DNA, which in sperm cells is typically lost during fertilisation, so all ... For example, it turns out that Wolff-Parkinson-White syndrome is a symptom of MERRF, but nobody picked that up at the time. ... Harry Cozens has been living with MERRF syndrome all his life, but it took nearly 20 years for his illness to be correctly ... For Harrys mother Mandy Norris, finding out that her son had MERRF syndrome, a mitochondrial disease that affects the muscles ...
The second syndrome is MERRF (myoclonus epilepsy with ragged-red fibers), characterized by myoclonus, weakness, ataxia, ... Like Barth syndrome, Sengers syndrome also affects primarily heart and muscle, with the distinctive additional clinical feature ... An example is the X-linked deafness-dystonia syndrome (Mohr-Tranebjaerg syndrome), characterized by progressive sensorineural ... These include 3 sporadic conditions: Pearson syndrome, Kearns-Sayre syndrome, and progressive external ophthalmoplegia with or ...
Kearns-Sayre syndrome, and MERRF (myoclonus epilepsy with ragged red fibres)17. For those considering ubiquinol supplementation ... Mechanisms of action and effects of the administration of Coenzyme Q10 on metabolic syndrome. J Nutr Intermed Metab. 2018;13:26 ... Mechanisms of action and effects of the administration of Coenzyme Q10 on metabolic syndrome. J Nutr Intermed Metab. 2018;13:26 ...
Mitochondrial disease was confirmed in 11 patients (13.3%), including few classical mitochondrial syndromes (MELAS, MERRF, ... Leigh and Kearns-Sayre syndrome) caused by pathogenic mtDNA variants (8.4%) and MDs caused by pathogenic variants in five nDNA ...
Nuclear DNA-encoded tRNAs targeted into mitochondria can rescue a mitochondrial DNA mutation associated with the MERRF syndrome ...
If myoclonic epilepsy with ragged red fibers (MERRF) syndrome is caused by at least one of four point mutations in ... Early Folinic Acid Supplementation Improves Symptoms of Kearns-Sayre Syndrome. If patients with Kearns-Sayre syndrome commonly ... For example, Leigh syndrome is associated with over 30 gene mutations, making it difficult to use single-gene identification as ... Whole Exome Sequencing Useful to Diagnose Leigh Syndrome. Even if two individuals are affected by the same disease, such as ...
... was born with MERRF syndrome, a rare disorder that affects the nervous system and can cause issues with hearing and mobility. ...
  • MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. (wikipedia.org)
  • Myoclonic epilepsy with ragged-red fibers (MERRF) is a disorder that affects many parts of the body, particularly the muscles and nervous system. (medlineplus.gov)
  • abstract = "Myoclonus is a possible manifestation of mitochondrial disorders, and its presence is considered, in association with epilepsy and the ragged red fibers, pivotal for the syndromic diagnosis of MERRF (myoclonic epilepsy with ragged red fibers). (unicatt.it)
  • Finally, this study reinforces the notion that myoclonus is not inextricably linked to epilepsy in MERRF patients, and therefore the term {"}myoclonic epilepsy{"} seems inadequate and potentially misleading. (unicatt.it)
  • As mentioned above, a few individuals with a mutation in the MT-TH gene have features of both myoclonic epilepsy with ragged-red fibers (MERRF) and MELAS. (encyclopedia.pub)
  • myoclonic epilepsy and ragged-red fibers (MERRF) syndrome, and Kearns-Sayre syndrome (sporadic multisystem mitochondrial pathology). (ima-press.net)
  • In Ohtahara syndrome, tonic spasms are the dominant seizure type, with little to no myoclonic seizures. (medscape.com)
  • Specific syndromes of progressive myoclonic epilepsy with key clinical features include Unverricht-Lundborg disease (Baltic myoclonus), myoclonus epilepsy with ragged red fibers (MERRF), neuronal ceroid lipofuscinoses (Batten disease), and sialidoses (cherry-red spot myoclonus syndrome). (medscape.com)
  • If myoclonic epilepsy with ragged red fibers (MERRF) syndrome is caused by at least one of four point mutations in mitochondrial DNA, then curing the disease should be as easy as giving new mitochondria to patients. (mitochondrialdiseasenews.com)
  • optic neuropathy) and MERRF (myoclonic epilepsy with ragged red fibers) are what kind of genetic disorder? (brainscape.com)
  • MT-TH gene mutations that cause MELAS and MERRF/MELAS overlap syndrome change single DNA building blocks (nucleotides) in the gene. (encyclopedia.pub)
  • First, MELAS and MERRF are completely different disorders, why simply the genotype can explain the difference between the two patients. (himjournals.com)
  • Novel mitochondrial DNA ND5 mutation in a patient with clinical features of MELAS and MERRF. (ima-press.net)
  • The primary features displayed on a person with MERRF include myoclonus, seizures, cerebellar ataxia, myopathy, and ragged red fibers (RRF) on muscle biopsy, leading to the disease's name. (wikipedia.org)
  • MERRF is characterized by muscle twitches (myoclonus), weakness (myopathy), and progressive stiffness (spasticity). (medlineplus.gov)
  • Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS) syndrome is a multisystem and progressive neurodegenerative disorder. (medscape.com)
  • Strokelike episodes and mitochondrial myopathy characterize MELAS syndrome. (medscape.com)
  • For individuals with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS) syndrome and for those with other oxidative phosphorylation (OXPHOS) disorders, metabolic therapies are administered to increase the production of adenosine triphosphate (ATP) and to slow or arrest the deterioration of this condition and other mitochondrial encephalomyopathies. (medscape.com)
  • The cause of MERRF disorder is due to mutations in the mitochondrial genome. (wikipedia.org)
  • Four point mutations in the genome can be identified that are associated with MERRF: m.A8344G, m.T8356C, m.G8361A, and m.G8363A. (wikipedia.org)
  • The remaining mutations only account for 10% of cases, and the remaining 10% of the patients with MERRF did not have an identifiable mutation in the mitochondrial DNA. (wikipedia.org)
  • Mutations in the MT-TK gene are the most common cause of MERRF, occurring in more than 80 percent of all cases. (medlineplus.gov)
  • Less frequently, mutations in the MT-TL1 , MT-TH , and MT-TS1 genes have been reported to cause the signs and symptoms of MERRF. (medlineplus.gov)
  • People with mutations in the MT-TL1 , MT-TH , or MT-TS1 gene typically have signs and symptoms of other mitochondrial disorders as well as those of MERRF. (medlineplus.gov)
  • Mutations that cause MERRF impair the ability of mitochondria to make proteins, use oxygen, and produce energy. (medlineplus.gov)
  • A small percentage of MERRF cases are caused by mutations in other mitochondrial genes, and in some cases the cause of the condition is unknown. (medlineplus.gov)
  • Most cases of MERRF are maternally inherited due to mtDNA mutations. (rarediseasesnetwork.org)
  • Four other mitochondrial DNA mutations have been reported to cause MERRF. (rarediseasesnetwork.org)
  • MERRF syndrome is caused by mutations in mitochondrial DNA, which in sperm cells is typically lost during fertilisation, so all mtDNA comes from the mother. (thelilyfoundation.org.uk)
  • For example, Leigh syndrome is associated with over 30 gene mutations, making it difficult to use single-gene identification as a cost-effective means of pinpointing Leigh syndrome. (mitochondrialdiseasenews.com)
  • The causes of MERRF syndrome are difficult to determine, but because it is a mitochondrial disorder, it can be caused by the mutation of nuclear DNA or mitochondrial DNA. (wikipedia.org)
  • The point mutation m.A8344G is most commonly associated with MERRF, in a study published by Paul Jose Lorenzoni from the Department of neurology at University of Panama stated that 80% of the patients with MERRF disease exhibited this point mutation. (wikipedia.org)
  • Less commonly, the disorder results from a new mutation in a mitochondrial gene and occurs in people with no family history of MERRF. (medlineplus.gov)
  • Approximately 80% of patients with the clinical characteristics of MELAS syndrome have a heteroplasmic A-to-G point mutation in the dihydrouridine loop of the transfer RNA (tRNA) Leu (UUR) gene at base pair (bp) 3243 (ie, 3243 A → G mutation). (medscape.com)
  • This mutation is commonly associated with the syndrome of mitochondrial encephalomyopathy, lactic acidosis and stroke like episodes (MELAS). (nih.gov)
  • No diabetic subject was shown to have the mtDNA mutation at position 8344 (tRNA(lys)) which has previously been described in the syndrome of mitochondrial encephalomyopathy and red-ragged fibres (MERRF). (nih.gov)
  • The most common MERRF mutation is A8344G, which accounted for over 80% of the cases (GeneReview article). (rarediseasesnetwork.org)
  • The mutation involved in this overlap syndrome replaces the nucleotide guanine with the nucleotide adenine at gene position 12147 (written as G12147A). (encyclopedia.pub)
  • It remains unknown why this mutation causes the overlapping features of MERRF and MELAS. (encyclopedia.pub)
  • Guillian-Barre syndrome has an extra AT in TATA box, which reduces the expression by 80%, because of this type of mutation? (brainscape.com)
  • Other features of MERRF include recurrent seizures (epilepsy), difficulty coordinating movements (ataxia), a loss of sensation in the extremities (peripheral neuropathy), and slow deterioration of intellectual function (dementia). (medlineplus.gov)
  • The absence seizures involved in this syndrome are often prolonged, with bilateral limb myoclonus, differentiating it from idiopathic childhood absence seizures, for which seizure duration involves seconds and can be accompanied with only mild jerks of eyes, eyelids, or eyebrows. (medscape.com)
  • The typical presentation of patients with MELAS syndrome includes features that comprise the name of the disorder, such as mitochondrial encephalomyopathy, lactic acidosis , and strokelike episodes. (medscape.com)
  • Researchers have not determined how changes in mtDNA lead to the specific signs and symptoms of MERRF. (medlineplus.gov)
  • Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ataxia. (unicatt.it)
  • Epilepsy syndromes that are included in the category of SGE are discussed below. (medscape.com)
  • Finsterer J. Photosensitive Epilepsy and Polycystic Ovary Syndrome as Manifestations of MERRF. (clinicalcases.eu)
  • If patients with Kearns-Sayre syndrome commonly are deficient in folate, logic would presume folinic acid therapy may benefit their symptoms. (mitochondrialdiseasenews.com)
  • Chronic progressive external ophthalmoplegia (CPEO) is the most common characteristic of Kearns-Sayre syndrome, which is one member of the family of mitochondrial myopathies. (mitochondrialdiseasenews.com)
  • The multisystem dysfunction in patients with MELAS syndrome may be due to both parenchymal and vascular OXPHOS defects. (medscape.com)
  • Most patients will not exhibit all of these symptoms, but more than one of these symptoms will be present in a patient who has been diagnosed with MERRF disease. (wikipedia.org)
  • Due to the multiple symptoms presented by the individual, the severity of the syndrome is very difficult to evaluate. (wikipedia.org)
  • In most cases, people with MERRF inherit an altered mitochondrial gene from their mother, who may or may not show symptoms of the disorder. (medlineplus.gov)
  • The prognosis for MERRF varies widely depending on age of onset, type and severity of symptoms, organs involved, and other factors. (rarediseasesnetwork.org)
  • This combination of signs and symptoms is called MERRF/MELAS overlap syndrome. (encyclopedia.pub)
  • Researchers have not determined how these genetic changes alter energy production in mitochondria or cause the varied signs and symptoms of MELAS or MERRF/MELAS overlap syndrome. (encyclopedia.pub)
  • In addition, L-arginine may modulate excitation by neurotransmitters at nerve endings and such effects might contribute to alleviation of strokelike symptoms in MELAS syndrome. (medscape.com)
  • Even if two individuals are affected by the same disease, such as Leigh syndrome, they may not have identical symptoms or causes of disease. (mitochondrialdiseasenews.com)
  • Ragged-red fibers (a characteristic microscopic abnormality observed in muscle biopsy of patients with MERRF and other mitochondrial disorders) Additional manifestations may include: hearing loss, short stature, exercise intolerance, dementia, multiple lipomas (fat tumors under the skin), cardiac defects, eye abnormalities, and speech impairment. (rarediseasesnetwork.org)
  • Approximately 55 percent were felt to have a single progressive neurodegenerative etiology, predominantly Alzheimer disease (AD), frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), dementia related to Parkinson disease (PD), and corticobasal degeneration (including corticobasal syndrome and many other phenotypes) [ 2 ]. (medilib.ir)
  • The remaining 45 percent of patients had the following etiologies: vascular-related cognitive change, alcohol-related cognitive change, Huntington disease (HD), cognitive impairment resulting from multiple sclerosis (MS), prion diseases, dementia related to Down syndrome (predominantly AD), and unknown/unclassified. (medilib.ir)
  • Estrella Salazar is a 17-year-old science genius from Nezahualcoyotl, Mexico whose 25-year-old sister, Perla, was born with MERRF syndrome, a rare disorder that affects the nervous system and can cause issues with hearing and mobility. (hiplatina.com)
  • The regional brain metabolic abnormalities in patients with these syndromes showed different features consistent with the distinct phenotypes. (neurology.org)
  • Malformation syndromes characterize various major and minor physical abnormalities with distinctive type of facial features. (epainassist.com)
  • MERRF syndrome affects different parts of the body, particularly the muscles and nervous system. (wikipedia.org)
  • For Harry's mother Mandy Norris, finding out that her son had MERRF syndrome, a mitochondrial disease that affects the muscles and nervous system, came with the added blow of learning that he had inherited the causal gene from her. (thelilyfoundation.org.uk)
  • Diagnosis and Management of Opsoclonus-Myoclonus-Ataxia Syndrome in Children: An International Perspective. (nih.gov)
  • Noonan syndrome is a common type of malformation syndrome case takes place with pediatric type of cardiomyopathy. (epainassist.com)
  • Mitochondrial disorders, including MERRF, may present at any age. (wikipedia.org)
  • MERRF is part of a group of conditions known as mitochondrial disorders, which affect an estimated 1 in 5,000 people worldwide. (medlineplus.gov)
  • As with all mitochondrial disorders, there is no cure for MERRF. (rarediseasesnetwork.org)
  • Capsule?CAPD: Continuous ambulatory peritoneal dialysis?Caps: Capsules?CAPS: Cryopyrin-Associated Periodic Syndromes disorders?CAPTIA Syph G: ?CAPTIA Syph M: ?CAST: Cardiac arrhythmia suppression trials?CAT: Computerized axial tomography?Cataplasm. (kuwaitpharmacy.com)
  • Mitochondrial DNA Depletion Syndrome (MDDS) is a group of autosomal recessive disorders that can lead to a significant reduction in the amount of mitochondrial DNA in affected tissues (e.g. muscle, liver, brain). (mitochondrialdisease.nhs.uk)
  • The pathogenesis of the strokelike episodes in MELAS syndrome has not been completely elucidated. (medscape.com)
  • The unusual strokelike episodes and higher morbidity observed in MELAS syndrome may be secondary to alterations in nitric oxide homeostasis that cause microvascular damage. (medscape.com)
  • Arginine administration during the acute and interictal periods of the strokelike episodes of the MELAS syndrome may represent a potential new therapy to reduce brain damage due to mitochondrial dysfunction, and is one of the most promising therapies to date. (medscape.com)
  • Based on the hypothesis that the strokelike episodes in MELAS syndrome are triggered by impaired vasodilation in the intracerebral arteries due to decreased levels of circulating NO, elevation of arginine and NO levels may ameliorate this effect. (medscape.com)
  • May be beneficial for treatment/prevention of strokelike episodes in MELAS syndrome. (medscape.com)
  • The category even includes mitochondrial abnormalities, like MERRF, MELAS, diseases in respiratory system or chain, defects in fatty acid oxidation, mitochondrial myopathies and Barth or Pompe syndromes. (epainassist.com)
  • The clinical manifestations of PCOS can be exacerbated by post-COVID syndrome. (clinicalcases.eu)
  • An individual displaying MERRFs syndrome will manifest not only a single symptom, but patients regularly display more than one affected body part at a time. (wikipedia.org)
  • It has been observed that patients with MERRF syndrome will primarily display myoclonus as a first symptom. (wikipedia.org)
  • Measurements of respiratory enzyme activities in intact mitochondria have revealed that more than one half of the patients with MELAS syndrome may have complex I or complex I + IV deficiency. (medscape.com)
  • In MERRF, only one of four patients showed an increase in the lactate/creatine resonance intensity ratio (an index of impairment of oxidative metabolism) in spectra from central (supraventricular) or occipital brain volumes, and this was small. (neurology.org)
  • Treatment with CoQ10 has been helpful in some patients with MELAS syndrome. (medscape.com)
  • Patients with traumatic brain injury, Down syndrome, and certain types of vascular disease are major patient groups that may or may not be included in these studies. (medilib.ir)
  • Lumpers" include virtually any type of SGE, whereas "splitters" require slow spike-wave complexes to make a diagnosis of Lennox-Gastaut syndrome. (medscape.com)
  • Challenges in diagnosis and understanding of natural history of polycystic ovary syndrome. (clinicalcases.eu)
  • Congenital central hypoventilation syndrome: diagnosis and management. (nih.gov)
  • The features of MERRF vary widely among affected individuals, even among members of the same family. (medlineplus.gov)
  • Study of this patient and his siblings showed a distinct form of late-onset diabetes associated with nerve deafness but no clinical features of the MELAS syndrome. (nih.gov)
  • X;Y translocation in a girl with short stature and some features of Turner's syndrome: cytogenetic and molecular studies. (clinicalcases.eu)
  • Harry had his genetic blood test there in August 2016, and in November we got confirmation that yes, it was MERRF. (thelilyfoundation.org.uk)
  • The etiology of polycystic ovary syndrome (PCOS) is not exactly known, but there are indications that genetic factors, exposure to androgen in early childhood, and obesity lead to a disruption of the hypothalamic-pituitary-ovarian axis and dysregulation of microRNAs. (clinicalcases.eu)
  • Trisomy 21 (down syndrome) is an example of what kind of genetic disorder? (brainscape.com)
  • Turner syndrome (45X) is what kind of genetic disorder? (brainscape.com)
  • Less commonly, people with MERRF develop fatty tumors, called lipomas, just under the surface of the skin. (medlineplus.gov)
  • Finsterer J. Mitochondrial Dysfunction in Polycystic Ovary Syndrome. (clinicalcases.eu)
  • Yet another pattern of regional metabolic abnormality was present in the MELAS syndrome, where proton spectroscopic imaging demonstrated focal localization of abnormally increased lactate/creatine and decreased N -acetylaspartate/creatine to the regions of the stroke-like lesions on conventional MR images. (neurology.org)
  • In secondary carnitine deficiency associated with MELAS syndrome, carnitine may restore generation of free CoA and avoid carnitine depletion. (medscape.com)
  • Ear drops?AutoPap: Computer-assisted cytology interpretation system?AV: Aortic valve?AV: Atrioventricular?A-V: Arteriovenous?AVERT: Atorvastatin Versus Revascularization treatment?AVID: ?AVM: Arteriovenous Malformation?AVNRT: AV nodal reentry tachycardia?AVP: Arginine vasopressin?AVR: Aortic valve replacement?AVR: Augmented V lead, right arm (ECG)?AVRT: ?AVS: Arteriovenous shunt?AWS: Alcohol withdrawal syndrome?AXR: Abdominal X ray?AZF: Azoospermia factor genes?AZT: Azidothymidine (zidovudine)?B & O: Belladonna and opium?B Bx. (kuwaitpharmacy.com)