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)

Anticipation refers to the progressively earlier onset and increase in disease severity in successive generations. We studied four families with hereditary dentatorubral-pallidoluysian atrophy (DRPLA), a neurodegenerative disease, and anticipation was present in the mode of inheritance. In subsequent generations DRPLA shows an earlier onset and more severe as well as additional symptoms. Older onset patients suffer from cerebellar ataxia with or without dementia, whereas younger onset patients present as progressive myoclonus epilepsy syndrome, which consists of mental retardation, dementia, and cerebellar ataxia as well as epilepsy and myoclonus. Anticipation with paternal transmission was significantly greater than with maternal transmission.
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PMID:Anticipation in hereditary dentatorubral-pallidoluysian atrophy. 800 97

Fourteen patients (10 boys, 4 girls) aged from 4 months to 14 years old were diagnosed with mitochondrial disease based on the clinical manifestations together with abnormal muscle mitochondrial morphologies. Their clinical diagnoses included Leigh syndrome, three; Menkes' syndrome, three; Kearns-Sayre syndrome, two; myoclonic epilepsy with ragged fibres, one; and infant-onset progressive myoclonic epilepsy, one; fatal infantile mitochondrial myopathy, one; fatty acid oxidation defect, two; and myopathy with cardiopathy, one. Organs involved other than muscles included central nervous system, ten; heart, six; eye, two; liver, two; and kidney, two. Clinical manifestations varied to include hypotonia, seizures, myoclonus, mental retardation, nystagmus, ataxia, ptosis, ophthalmoplegia, retinal degeneration, muscle atrophy, spasticity etc. Nine had an abnormal rise in lactate after glucose loading. Ragged-red fibres were found in four patients. Abnormal mitochondrial morphology included abnormal accumulation, abnormal cristae pattern of tubular, concentric, or parallel form, some contained osmiophilic inclusion bodies. One patient of Leigh syndrome had had brain necropsy which showed intramyelin splitting of myelinated axons.
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PMID:Clinical manifestation of mitochondrial diseases in children. 821 54

A 35-year-old female was reported who presented early onset and slowly progressive ataxia and retrocollis which appeared at the age of nine. On admission, neurological examination revealed cerebellar ataxia, dystonia of the neck and the right arm, myoclonus of the neck and the shoulder, slight mental retardation, supranuclear upper gaze palsy, and sensorineural hearing loss. Laboratory examination showed high serum CK activity. Electromyography and muscle biopsy findings suggested slight muscular involvement. CSF level of HVA and 5-HIAA were reduced. MRI demonstrated marked cerebellar atrophy and slight atrophy of the brain stem. To our knowledge, the characteristic combination of the neurological sign in this case has not been reported. This case was compared with EOCA (early onset cerebellar ataxia with retained tendon reflexes) and other juvenile onset cerebellar ataxia and dystonia.
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PMID:[A case of juvenile onset ataxia with dystonia, myoclonus, sensorineural hearing loss and mental retardation]. 826 7

We report myoclonic epilepsy with ragged-red fibers (MERRF) syndrome in a Chinese family with confirmed mitochondrial DNA point mutation. Six members of the family including the grandmother, two siblings, and three grandchildren were affected. Among them, action myoclonus was seen in five; short stature, muscle weakness, and mental retardation in four; lactic acidosis, hearing impairment, and ataxia in two; and seizures in one. Muscle biopsy from two affected siblings revealed ragged-red fibers and abundant subsarcolemmal mitochondria with paracrystalline inclusions. Pedigree analysis suggests a maternal transmission. Analysis of mitochondrial DNA showed a point mutation from A to G at the 8344th nucleotide position located in the tRNA(Lys) gene. To our knowledge, this is the first report of MERRF syndrome with such genetic defect from a Chinese family. The present and previous reports support the notion that mitochondrial DNA point mutation at the 8344th nucleotide position is the most common cause of MERRF syndrome.
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PMID:Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome: report of a Chinese family with mitochondrial DNA point mutation in tRNA(Lys) gene. 793 36

The term of dentatorubral and Pallidoluysian atrophy (DRPLA) was first introduced by Smith, who proposed that there was a combination of cerebellar ataxia with choreoathetosis based on DRPL lesions. In 1972, Naito et al. reported two families with progressive myoclonus epilepsy (PME) syndrome with cerebellar ataxia, and hyperactive deep tendon reflexes. In 1977, Oyanagi et al. reported 4 autopsied cases of PME, and pointed out degenerative lesions in the DRPL systems. In 1982, Naito and Oyanagi reported this type of PME to be hereditary DRPLA, with a clinicopathological disease entity. This type of PME with DRPLA has been made a major category, especially in Japan. In this article, clinicopathological features of the hereditary DRPLA will be reviewed on the basis of 45 patients with this disease. The disease was inherited as an autosomal dominant fashion, and induces a wide rage of clinical features depending upon the age of onset, ranging from 3 years to 69 years of age. The initial symptoms were variable according to the age of onset and mental retardation was the most prominent symptom in the patients in which the disease started in the first decade and with an epileptic seizure in the second decade. In the following next two decades, the incidence of epileptic seizure, as initial symptoms was decreased to 23% and gait disturbance and ataxia in 38% of the patients, which increased to 73% in the 5th and 6th decades. The cardinal symptoms of hereditary DRPLA includes mental retardation, epileptic seizure and myoclonus, cerebellar ataxia with gait disturbances, psychological symptoms including clonus, cerebellar ataxia with gait disturbances, psychological symptoms including character changes, and dementia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Hereditary dentatorubro-pallidoluysian atrophy (DRPLA): clinical studies on 45 cases]. 827 85

The clinical, genetic, and neuroradiologic characteristics of dentatorubral-pallidoluysian atrophy (DRPLA) are delineated in six patients from three generations of a Japanese family. The clinical characteristics of the disease varied, the age at onset depending on patients with juvenile-onset were characterized by myoclonus, epilepsy, and mental retardation whereas cerebellar ataxia, choreoathetosis, and dementia were typical of adult- and senile-onset patients. All affected individuals showed one expanded allele with the repeat number of CAG at the DRPLA locus, ranging from 58 to 82, and a normal allele, ranging from 10 to 21. The most severely affected patient, a case of maternal transmission and with the largest allele, became bedridden in a vegetative state by age 12. On the CT and MRI, varying degrees of brain atrophy were present in all patients. T2-weighted MRI in patients with senile-onset showed symmetric high-signal lesions in the cerebral white matter, globus pallidus, thalamus, midbrain, and pons. However, MRI in younger patients revealed no such lesions and CT failed to demonstrate lesions in the globus pallidus and brain stem. Thus, intrafamilial heterogeneity of DRPLA was also evident on MRI. High-signal lesions involving both, subcortical white matter and thalamus may be characteristics of senile-onset patients and may correlate with their dementia.
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PMID:Dentatorubral-pallidoluysian atrophy (DRPLA): clinical, genetic, and neuroradiologic studies in a family. 858 78

Sialidase (neuraminidase, EC 3.2.1.18) catalyses the hydrolysis of terminal sialic acid residues of glyconjugates. Sialidase has been well studied in viruses and bacteria where it destroys the sialic acid-containing receptors at the surface of host cells, and mobilizes bacterial nutrients. In mammals, three types of sialidases, lysosomal, plasma membrane and cytosolic, have been described. For lysosomal sialidase in humans, the primary genetic deficiency results in an autosomal recessive disease, sialidosis, associated with tissue accumulation and urinary excretion of sialylated oligosaccharides and glycolipids. Sialidosis includes two main clinical variants: late-onset, sialidosis type I, characterized by bilateral macular cherry-red spots and myoclonus, and infantile-onset, sialidosis type II, characterized by skeletal dysplasia, mental retardation and hepatosplenomegaly. We report the identification of human lysosomal sialidase cDNA, its cloning, sequencing and expression. Examination of six sialidosis patients revealed three mutations, one frameshift insertion and two missense. We mapped the lysosomal sialidase gene to human chromosome 6 (6p21.3), which is consistent with the previous chromosomal assignment of this gene in proximity to the HLA locus.
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PMID:Cloning, expression and chromosomal mapping of human lysosomal sialidase and characterization of mutations in sialidosis. 905 50

A 16-year-old boy with mitochondrial encephalomyopathy had seizures, short stature, muscle weakness, progressive hearing loss, mental retardation, and myoclonus. His cranial computed tomography showed progressive calcification in the basal ganglia and cerebral atrophy. Muscle biopsy revealed many ragged-red fibers with variable cytochrome c oxidase activity and some strongly succinate dehydrogenase-reactive blood vessels. Sequence analysis of the entire mitochondrial DNA revealed a novel point mutation in the tRNA-Thr gene at nucleotide pair 15915. Serum lactate levels were decreased by high-dose coenzyme Q10 (CoQ10) therapy. The spectral power density, a parameter of background activity on electroencephalography, was markedly improved after additional administration of idebenone. After initiation of combined CoQ10 and idebenone therapy, the clinical abnormalities did not progress for 16 months.
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PMID:Mitochondrial encephalomyopathy with 15915 mutation: clinical report. 936 99

The authors report a long-term follow-up of 11 new subjects with benign myoclonic epilepsy. There were some unusual clinical features such as the need for dual therapy in 45.5% of subjects, and the presence of non-epileptic myoclonus in 54.5%, neither of which influenced the prognosis. Neuropsychological and behavioral evolution was less favorable in 45.5% of patients (mental retardation, school learning problems, attention deficit disorder, hyperkinesia, aggressiveness, irritability, negativism). The less favorable neuropsychological outcome might be related to additional interacting factors such as personal antecedents, seizure onset and antiepileptic treatment.
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PMID:Benign myoclonic epilepsy: long-term follow-up of 11 new cases. 940 94

Rett syndrome (RS) is one of the most frequent causes of mental retardation in females. As there are no known biochemical, genetic, or morphological markers, diagnosis is based on clinical phenotype including severe dementia, autism, truncal ataxia/apraxia, loss of purposeful hand movements, breathing abnormalities, stereotypies, seizures, and extrapyramidal signs. Myoclonus, although reported in some series, has never been characterized. We studied 10 RS patients, age 3 to 20 years, and observed myoclonus in 9. Severity of myoclonus did not correlate with that of the other symptoms or with age. Multifocal, arrhythmic, and asynchronous jerks mainly involved distal limbs. Electromyographic bursts lasted 48 +/- 12 msec. Burst-locked electroencephalographic averaging generated a contralateral centroparietal premyoclonus transient preceding the burst by 34 +/- 7.2 msec. Motor evoked potentials showed normal latencies, indicating integrity of the corticospinal pathway. Somatosensory evoked potentials were enlarged. The C-reflex was hyperexcitable and markedly prolonged (62 +/- 4.3 msec), mainly due to increase in cortical relay time (28.4 +/- 4.5 msec). We conclude that RS patients show a distinctive pattern of cortical reflex myoclonus with prolonged intracortical delay of the long-loop reflex.
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PMID:Cortical reflex myoclonus in Rett syndrome. 954 28


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