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)

Myoclonus epilepsy with ragged-red fibers (MERRF) has been shown to be associated with a specific point mutation at the nucleotide 8344 in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). We screened 6 patients with clinically diagnosed MERRF and 1 patient with ocular myopathy for point mutations in the tRNA(Lys) gene, using single strand conformation polymorphism (SSCP) analysis, which can detect even a 1-basepair difference between 2 DNA sequences. Using SSCP and consequent DNA sequencing, we identified the known MERRF mutation in 4 out of 6 MERRF patients, as well as in 1 patient with a new clinical phenotype associated with this mutation: progressive external ophthalmoplegia, muscle weakness and a lipoma, but no myoclonus or epilepsy. Two of the patients with clinical MERRF had neither the MERRF-mutation nor any other mutations in the tRNA(Lys) gene. Using SSCP analysis, we also detected a new polymorphism in 1 patient. Thus, SSCP analysis can be applied to search effectively and rapidly for point mutations or polymorphisms in mitochondrial DNA.
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PMID:Use of single strand conformation polymorphism analysis to detect point mutations in human mitochondrial DNA. 143 90

We performed a clinicopathological study on 12 autopsied cases of dentatorubropallidoluysian atrophy. They were divided into 3 groups according to the age at onset: juvenile type (6 cases), early adult type (4 cases) and late adult type (2 cases). In juvenile type showing progressive myoclonus epilepsy (PME) syndrome, degeneration of the globus pallidus was more marked than that of the dentate nucleus. Mild to moderate atrophy was seen in the brain stem and spinal cord. In early adult type showing milder symptom of myoclonus and epilepsy, the globus pallidus and dentate nucleus were equally degenerated to various extents in most cases. Atrophy of the brain stem and spinal cord was mild to moderate in degree. In late adult type without PME syndrome, degeneration of the dentate nucleus was more marked than that of the globus pallidus. The brain stem and spinal cord were severely atrophic. On the other hand, the cases showing severe dentate lesion had a tendency to show severe atrophy of the brain stem and spinal cord. We consider that development of myoclonus, epilepsy and choreoathetoid movement in DRPLA patients has close relation to the extent of not only degeneration of the globus pallidus and dentate nucleus, but also atrophy of the brain stem and spinal cord.
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PMID:[Dentatorubropallidoluysian atrophy (DRPLA): comparative pathological study on clinical groups classified into juvenile, early adult and late adult types]. 156 29

We describe a family with hereditary dentatorubropallidoluysian atrophy (DRPLA). 4 patients through 3 successive generations showed a wide clinical variety. The female proband with onset in the elderly developed choreiform involuntary movement, dementia, hyperreflexia and, at the progressive stage, mild ataxia. However she had never displayed epilepsy and myoclonus. The 2 sons showed dementia, choreoathetoid movement and ataxia. The grandson developed typical signs and symptoms of progressive myoclonus epilepsy. The brain CT in the proband showed severe cerebellar and brain stem atrophy, moderate cerebral cortical atrophy and diffuse low density lesions in the deep cerebral white matter. Her neuropathological examination revealed the atrophy and gliosis of cerebral and cerebellar white matter concomitant with both dentatorubral and pallidoluysian system degeneration. The present study indicates that hereditary DRPLA can include multiple clinical variants even in the same family and the degeneration of cerebral and cerebellar white matter besides dentatorubral and pallidoluysian system.
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PMID:[Hereditary dentatorubropallidoluysian atrophy--clinical variants in a family and degeneration of cerebral white matter in a proband]. 159 Nov 6

We describe a young man with a progressive neurological disorder including myoclonus, mental retardation, muscle weakness and a mitochondrial myopathy (myoclonus epilepsy and ragged red fibres--MERRF). Multiple abnormalities of the mitochondrial respiratory chain in skeletal muscle are shown by direct measurement of the flux through the individual complexes, low-temperature redox spectroscopy and decreased immunodetectable subunits of complexes I and IV by immunoblotting. No abnormality of mitochondrial DNA was found. This is the first report of combined defects of complexes I, III and IV as a cause of this clinical syndrome. However, we propose that the occurrence of multiple respiratory chain defects may be more common than previously recognised and that this particular combination of defects, involving complexes I, III and IV, may be the predominant biochemical abnormality in MERRF.
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PMID:Multiple defects of the mitochondrial respiratory chain in a mitochondrial encephalopathy (MERRF): a clinical, biochemical and molecular study. 164 12

A progressive, hereditary disease has been observed in Basset Hounds, which appears clinically and neuromorphologically as myoclonus epilepsy (ME) and is similar to Lafora-Glueck disease in humans. The characteristic intracellular accumulations are typical myoclonus inclusion bodies. Four forms of inclusion bodies (IB) can be distinguished: a) very small, homogeneous, PAS-positive IBs, b) IBs consisting of an accumulation of PAS-positive particles, c) IBs with a concentric internal structure and a smooth or radial outer zone, and d) IBs with a homogeneous center, concentric layering, light intermediate zone, and a smooth outer zone. The occurrence of IBs is restricted largely to nerve cells. Here they are located mainly in pericarya, to a lesser extent in dendrites, and rarely in the neurites of the peripheral nervous system. IBs are also found in samples of skeletal muscle where they lie between myofibrils or beneath the sarcolemma. They are slightly basophilic in HE-staining and markedly PAS-positive. In transmission electron micrographs IBs prove to consist of chain-like filamentous material of varying density with focal concentrations. They are similar to IBs of the brain. Both muscular and neuronal IBs lack surrounding membranes. Diagnosis of Lafora disease in dogs by examination of muscle biopsies is discussed.
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PMID:[Lafora disease (progressive myoclonic epilepsy) in the Bassett hound--possibility of early diagnosis using muscle biopsy?]. 165 70

Progressive myoclonus epilepsy of Univerricht-Lundborg type is a clinically defined entity among the progressive myoclonus epilepsies. It is an autosomal recessive disorder. The underlying biochemical defect is unknown. We used linkage analysis to localize the gene in 12 families with the aid of polymorphic DNA markers. Close linkage was detected with three markers on distal chromosome 21. The loci BCEI and D21S154 gave the highest positive logarithm-of-odds (lod) scores of 5.49 and 4.25, respectively, at zero recombination. The third locus, D21S112, gave a lod score of 6.91 at a recombination fraction of 0.034. There was no evidence of heterogeneity. Multipoint lod scores calculated against a fixed map of the three marker loci gave a maximum four-point lod score of 10.08 at a location of the disease gene at 6.0 centimorgans distal to locus BCEI and 0.8 centimorgan proximal to locus D21S154. As markers BCEI and D21S154 have previously been localized to 21q22.3 by physical methods, our findings place the EMP1 gene locus (for progressive myoclonus epilepsy of the Unverricht-Lundborg type) in chromosome 21 band q22.3. This finding provides an opportunity to test several other epilepsy phenotypes, particularly the so-called Ramsay Hunt syndrome, for linkage to the same locus. It also is a starting point toward isolating and characterizing the gene and its protein product.
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PMID:Localization of a gene for progressive myoclonus epilepsy to chromosome 21q22. 167 90

Immediately after a patient with myoclonus epilepsy smoked a nicotine-containing cigarette, tetraparesis and hyperreflexia with ankle clonus developed, but disappeared within several minutes. During paresis, the H-reflex size of the soleus muscle increased, EEG showed more slow waves than before smoking, and the cerebral perfusion increased around the motor cortex as shown by single photon emission CT. A similar effect occurred when the patient chewed nicotine gum, and smoking a cigarette with a high nicotine content induced severe positive and negative myoclonus after the development of tetraparesis. Administration of the C6-type nicotinic antagonist mecamylamine not only countered the smoking effect, but ameliorated the spontaneous positive and negative myoclonus. Mecamylamine may prove useful for the treatment of positive and negative myoclonus in myoclonus epilepsy.
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PMID:Nicotine-sensitive paresis. 173 70

Four siblings aged 12-18 years with progressive myoclonus epilepsy demonstrated a subclinical stage at the age of 9-11 years, with visual blackouts and polyspike electroencephalographic (EEG) activity on photic stimulation, an early myoclonic stage at the age of 12-15 years, with increasing segmental, stimulus-sensitive myoclonus, occasional nocturnal buildup myoclonic "cascade" seizures, slowing of EEG alpha-activity, episodic 4-6 Hz bilateral sharp waves and polyspikes with myoclonias on photic stimulation, and a disabling myoclonic stage at the age of 16-18 years, with periodic generalized myoclonias, nocturnal myoclonic "cascade" seizures, ataxia, dysarthria, mental changes, intermittent wheelchair dependency, and continuous EEG slow waves with polyspikes and intense myoclonias on photic stimulation. One of the siblings died at the age of 18 years with no apparent cause of death. Treatment with antiepileptic drugs other than valproate may have contributed but none of the siblings were ever treated with phenytoin. Extensive clinical and laboratory investigations revealed no abnormalities and excluded other known possible causes of progressive myoclonus epilepsy. The diagnosis was consistent with Unverricht-Lundborg disease and rested on typical age of onset, clinical signs, EEG, and evoked response abnormalities. Buildup myoclonic seizures are typical in advanced stages of Unverricht-Lundborg disease. We have labeled these myoclonic "cascade" seizures. A typical seizure was studied with video-EEG and cardiorespiratory monitoring. Characteristics revealed were onset with continuous arrhythmic myoclonic jerks followed by intense rhythmic myoclonus with increasing muscle tone that successively reduced the amplitude of the jerks. The EEG during the whole seizure showed intense polyspike activity. Obstructive apnea was seen at the peak of the seizure. There were no cardiac dysrhythmias. Consciousness was normal or only slightly impaired. Postictal drowsiness was not observed. Myoclonic "cascade" seizures are easily confused with generalized tonic-clonic seizures.
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PMID:Clinical and neurophysiological development of Unverricht-Lundborg disease in four Swedish siblings. 174 64

We have investigated the effect of piracetam on photoparoxysmal responses in 3 patients with progressive myoclonus epilepsy. With doses of up to 10 g/day, elimination of photoparoxysmal responses was achieved in all 3 patients. Corresponding to EEG improvement, the clinical performance improved slightly in 2 patients and definitely in 1 patient when piracetam was added to their medication of valproate and clonazepam. According to our data, medical treatment of myoclonus with piracetam is justified particularly in myoclonus of cortical origin.
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PMID:Abolition of photoparoxysmal response in progressive myoclonus epilepsy. 175 63

A 22-year-old woman with progressive myoclonus epilepsy associated with the first and second branchial syndrome is described. Clinical features included generalized convulsive seizure, myoclonus, cerebellar ataxia and intellectual deterioration with micrognathia and malformation of auricles. She was initially suspected of mitochondrial encephalomyopathy, but the analysis of muscle biopsy and mitochondrial enzyme activities was negative. Her micrognathia and malformation of auricles were diagnosed as the first and second branchial syndrome. The case of progressive myoclonus epilepsy associated with this syndrome has never been reported, and the relationship between them remains unknown.
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PMID:[A case of progressive myoclonus epilepsy with the first and second branchial syndrome]. 176 51


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