Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Benign adult familial myoclonic epilepsy (BAFME or FAME) is an autosomal dominant condition, characterized by shivering-like tremors of cortical origin, myoclonus, and epilepsy. Linkage to chromosomes 2p11.1-q12.2 and 8q23.1-q24.11 has been reported in Japanese and Italian families, respectively. We aimed to determine whether a common founder haplotype was shared by five BAFME families from southern Italy and attempted preliminary genotype-phenotype correlation analyses. Five Italian BAFME families were identified. One family has not been previously reported. DNA from 53 affected individuals was genotyped with highly polymorphic microsatellite markers spanning chromosomes 2p11.1-q12.2 and 8q23.1-q24.11. Multipoint linkage analysis was performed using LINKMAP 5.1 software assuming an autosomal dominant trait with 0.99 penetrance and frequency of 0.001. Significant linkage was found on chromosome 2p11.1-q12.2 and a maximum cumulative lod score of 18.5 was found for markers D2S2161 and D2S388. The haplotype "5332" of adjacent markers D2S388, D2S2216, D2S113, and D2S2175 segregates with the disease in all families indicating that the same mutation inherited from a common ancestor segregates in these families. Preliminary genotype-phenotype showed that patients carrying the disease haplotype show minor clinical differences, suggesting that expressivity of the founder mutation is not markedly influenced by other factors. The identification of causative mutations in BAFME requires an extensive and collaborative screening effort.
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PMID:Benign adult familial myoclonic epilepsy (BAFME): evidence of an extended founder haplotype on chromosome 2p11.1-q12.2 in five Italian families. 1823 15

MERRF is an acronym of myoclonus epilepsy associated with ragged-red fibers and was first reported as a new nosological entity belonging to mitochondrial encephalomyopathies in San Remo symposium on "Mitochondrial Pathology" in 1982. MERRF was named Fukuhara disease by Rowland (1983). The first reported patient had been diagnosed as having Ramsay Hunt syndrome associated with Friedreich's ataxia. However, nowadays, the previously reported cases as having Ramsay Hunt syndrome associated with Friedreich's ataxia are regarded as having been suffered from MERRF. The history in establishing the nosological entity of MERRF was described. Patients with MERRF develop myoclonus, epileptic seizures, cerebellar ataxia, dementia, sensorineural hearing disturbance, optic atrophy, muscular wasting, and foot deformities at the advanced stage. Pathological findings show degeneration of the dentate nuclei, globus pallidus, and red nuclei, substantia nigra, inferior olivary nuclei, cerebellar cortex, and spinal cord. The posterior columns, the spinocerebellar tracts, and Clark's columns are degenerating in the spinal cord. The pyramidal tracts never show a severe degeneration as in Friedreich's ataxia. The skeletal muscles show mitochondrial abnormalities histologically and electron microscopically. Clinical features of MERRF are not necessarily uniform in the early stage and muscle biopsy findings are also very mild in some patients with MERRF, necessitating genetic analysis for diagnosis. Most of patients show a point mutation (A --> G) of nt 8344 in mitochondrial DNA.
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PMID:[Fukuhara disease]. 1823 33

MERRF is typically characterized by myoclonus, generalized seizures and ragged-red fibers in muscular biopsy. We report a family (harbouring the A8344G mutation) with a late onset of the disease and an uncommon clinical manifestation, including episodes of reversible respiratory failure, the presence of ophthalmoplegia, and the absence of seizures and myoclonus in most subjects. We conducted histochemical, biochemical and molecular genetic studies. Mutation analysis revealed that the level of mutated mitochondrial DNA (mtDNA) was above 80% in the skeletal muscle of all siblings. Nevertheless, one severely affected individual did neither present cytochrome c oxidase-negative fibers nor ragged-red fibers in the skeletal muscle biopsy. These data extend the phenotypic range associated with the MERRF syndrome. We suggest that the analysis of mtDNA could be of importance in many cases of unclear multisystem disorders in later life.
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PMID:Unusual presentations of patients with the mitochondrial MERRF mutation A8344G. 1865 54

A 6-year-old girl was experiencing repetitive involuntary and massive jerks immediately involving limbs and trunk. The first motor events appeared approximately at 1 year old and only 5 months after a back trauma. Myoclonus became progressively more frequent and more violent, causing episodes of falls. Neurological examination showed jerks characterized by upper limb abduction, lower limb abduction, and head-body hyperextension. Apart from these motor events, the neurological examination was normal. The results of vitamin B(12) and folate, antinuclear antibody, anti-DNA, anti-Tiroglobulin, anti-thyroid peroxidase antibody, lupus anticoagulant, anti-cardiolipin antibody, rheumatoid factor, and C3 and C4 were unexceptional. Electroencephalography and brain and spinal magnetic resonance imaging were unremarkable. Electromyographic records with surface electrodes showed that duration of myoclonic jerks was ranging from 100 to 300 ms. We thought she had propriospinal myoclonus because of presence of the spreading through the shoulder, upper limbs, and lower limbs in addition to thoracolumbar paraspinal muscles.
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PMID:Propriospinal myoclonus in a child. 2019 68

Myoclonic epilepsy and ragged-red fibers (MERRF) syndrome is a rare disorder characterized by myoclonus, muscle weakness, cerebellar ataxia, heart conduction block, and dementia. It has been documented that 80-90% of the patients with MERRF syndrome are caused by the A8344G mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). We and other investigators have reported that the mtDNA mutation results in not only inefficient generation of adenosine triphosphate but also increased production of reactive oxygen species (ROS) in cultured cells harboring A8344G mutation of mtDNA. In addition, we found an imbalance in the gene expression of antioxidant enzymes in the skin fibroblasts of MERRF patients. The mRNA, protein, and enzyme activity levels of manganese-superoxide dismutase were increased, but those of Cu,Zn-SOD, catalase, and glutathione peroxidase did not show significant changes. Recently, we showed that the excess ROS could damage voltage-dependent anion channel, prohibitin, Lon protease, and aconitase in the MERRF cells. Moreover, there was a dramatic increase in the gene expression and activity of matrix metalloproteinase 1, which may contribute to the cytoskeleton remodeling involved in the weakness and atrophy of muscle commonly seen in MERRF patients. Taken together, we suggest that mtDNA mutation-elicited oxidative stress, oxidative damage, and altered gene expression are involved in the pathogenesis and progression of MERRF syndrome.
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PMID:Mitochondrial DNA mutation-elicited oxidative stress, oxidative damage, and altered gene expression in cultured cells of patients with MERRF syndrome. 2041 57

Here, we present a male infant with clinical signs of typical Leigh syndrome. The first symptom, myoclonus was presented already on the 5th day of life; at 7 months of age limb convulsions and cerebral paresis with hypotonia were developed. At the age of 11 months, MRI verified increased signal intensity in the entire mesencephalon and medulla oblongata; while gray matter proton spectroscopy revealed presence of lactate increase in the brain. At age of 17 months, the child died in cardiorespiratory arrest. After autopsy, the diagnosis of Leigh syndrome was established; using DNA isolated from skeletal muscle and liver, heteroplasmic (>50%) mitochondrial 11777C>A was detected in the fourth subunit of NADH dehydrogenase enzyme (MTND4) encoding gene, which causes Arg --> Ser replacement. The mutation was also detected in low copy number in blood of mother. Albeit this mutation type is well recognized as a typical mtDNA mutation, according the reports available on the PubMed, this mutation was described only in four patients with wide phenotypic variations; here, we reviewed the characteristic clinical features of them. Taken together, the earliest onset of symptoms, the nature of the first presentation signs, the most rapid progression, the character of minor additional symptoms, and the early fatal outcome differentiate the phenotypic variant of the proband presented here from cases reported so far by others.
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PMID:Mitochondrial DNA 11777C>A mutation associated Leigh syndrome: case report with a review of the previously described pedigrees. 2050 85

Myoclonic epilepsy of Lafora (EPM2) is a severe autosomal recessive disorder. The onset in adolescence, generalized seizures, severe myoclonus, dementia and a rapid malignant course with death in 4-8 years after the onset are characteristic features of EPM2. The disease has a specific pathological feature, intracellular polyglucosan inclusions (Lafora bodies) in the brain, liver, skin and muscles. Two genetic forms are known, one of which (EPM2A) is caused by mutations in the laforin gene and another (EPM2B)--by mutations in the malin gene. We report a case of EPM2A in a 17-year-old girl of mixed Russian-Ukrainian ethnicity. The disease lasted for almost four years by the time of the examination but the girl still had no dementia. A previously described laforin mutation Tyr86Stop in the homozygous state was detected and Lafora bodies were found in the skin and muscles. Various anticonvulsants produced no effect or a slight and unstable effect. In the following several months, the disease progressed quickly, the girl became severely disabled and demented and died in 19 years old, 5.5 years after the disease onset. This is a first Russian case confirmed by DNA testing.
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PMID:[Myoclonic epilepsy of Lafora: a case report]. 2087 69

Myoclonus can be classified as physiologic, essential, epileptic, and symptomatic. Animal models of myoclonus include DDT and posthypoxic myoclonus in the rat. 5-Hydrotryptophan, clonazepam, and valproic acid suppress myoclonus induced by posthypoxia. The diagnostic evaluation of myoclonus is complex and involves an extensive work-up including basic electrolytes, glucose, renal and hepatic function tests, paraneoplastic antibodies, drug and toxicology screens, thyroid antibody and function studies, neurophysiology testing, imaging, and tests for malabsorption disorders, assays for enzyme deficiencies, tissue biopsy, copper studies, alpha-fetoprotein, cytogenetic analysis, radiosensitivity DNA synthesis, genetic testing for inherited disorders, and mitochondrial function studies. Treatment of myoclonus is targeted to the underlying disorder. If myoclonus physiology cannot be demonstrated, treatment should be aimed at the common pattern of symptoms. If the diagnosis is not known, treatment could be directed empirically at cortical myoclonus as the most common physiology. In cortical myoclonus, the most effective drugs are sodium valproic acid, clonazepam, levetiracetam, and piracetam. For cortical-subcortical myoclonus, valproic acid is the drug of choice. Here, lamotrigine can be used either alone or in combination with valproic acid. Ethosuximide, levetiracetam, or zonisamide can also be used as adjunct therapy with valproic acid. A ketogenic diet can be considered if everything else fails. Subcortical-nonsegmental myoclonus may respond to clonazepam and deep-brain stimulation. Rituximab, adrenocorticotropic hormone, high-dose dexamethasone pulse, or plasmapheresis have been reported to improve opsoclonus myoclonus syndrome. Reticular reflex myoclonus can be treated with clonazepam, diazepam and 5-hydrotryptophan. For palatal myoclonus, a variety of drugs have been used.
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PMID:Myoclonus. 2149 98

We present a Japanese family suffering from mitochondrial encephalomyopathy associated with a T-to-C transition at mitochondrial DNA (mtDNA) nucleotide position 3291. Clinical manifestations of the patients include cerebellar ataxia with myopathy, recurrent headache, and myoclonus and epilepsy. The phenotypic variation among the affected members of a single family and the mutational analysis showing maternal inheritance in a heteroplasmic fashion are consistent with well-recognized phenomena associated with many pathogenic point mutations of mtDNA tRNA genes. The 3291 mutation is a rare mtDNA mutation whose clinical presentation had only been reported in three sporadic cases. This is the first report of a family segregating the 3291 mutation with multigenerational matrilinear recurrence of mitochondrial encephalopathy. Our findings provide conclusive evidence for the pathogenicity of the 3291T > C mutation in mtDNA and its characteristic clinical heterogeneity.
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PMID:Variable phenotypes in a family with mitochondrial encephalomyopathy harboring a 3291T > C mutation in mitochondrial DNA. 2186 73

Mitochondrial respiratory chain disorders are relatively common inborn errors of energy metabolism, with a combined prevalence of one in 5000. These disorders typically affect tissues with high energy requirements, and cerebral involvement occurs frequently in childhood, often manifesting in seizures. Mitochondrial diseases are genetically heterogeneous; to date, mutations have been reported in all 37 mitochondrially encoded genes and more than 80 nuclear genes. The major genetic causes of mitochondrial epilepsy are mitochondrial DNA mutations (including those typically associated with the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS] and myoclonic epilepsy with ragged red fibres [MERRF] syndromes); mutations in POLG (classically associated with Alpers syndrome but also presenting as the mitochondrial recessive ataxia syndrome [MIRAS], spinocerebellar ataxia with epilepsy [SCAE], and myoclonus, epilepsy, myopathy, sensory ataxia [MEMSA] syndromes in older individuals) and other disorders of mitochondrial DNA maintenance; complex I deficiency; disorders of coenzyme Q(10) biosynthesis; and disorders of mitochondrial translation such as RARS2 mutations. It is not clear why some genetic defects, but not others, are particularly associated with seizures. Epilepsy may be the presenting feature of mitochondrial disease but is often part of a multisystem clinical presentation. Mitochondrial epilepsy may be very difficult to manage, and is often a poor prognostic feature. At present there are no curative treatments for mitochondrial disease. Individuals with mitochondrial epilepsy are frequently prescribed multiple anticonvulsants, and the role of vitamins and other nutritional supplements and the ketogenic diet remain unproven.
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PMID:Mitochondrial disease and epilepsy. 2228 95


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