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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The syndrome of myoclonus, epilepsy, and mental deficiency is observed in a number of distinct nosologic entities differing with respect to clinical course, (--) pathologic, and biochemical findings. Genetically, the heterogeneity within this group of disorders is shown by the occurrence of autosomal recessive and dominant forms with incomplete penetrance. In this paper we report on a sibship with at least four affected males suffering from progressive myoclonus epilepsy, ataxia, and mental deterioration. The syndrome is probably X-linked, as suggested by the maternal transmission and mild, variable symptoms in some female carriers. In a survey of the literature we have found another pedigree suggesting X-linked inheritance of this variant of progressive myoclonus epilepsy.
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PMID:Progressive myoclonus epilepsy. A variant with probable X-linked inheritance. 11 32

The long-term prognosis of 185 children with epilepsy, who continued to attend the Clinic for Epileptic Children, the Department of Pediatrics, the University of Tokyo, beyond the age of 18 years, was reported. The length of follow-up varied from three to 20 years, but most of them were followed longer than 10 years. The presumed etiology in these children was divided into a cryptogenic group (124, 67.0%) and a symptomatic group (61). The types of seizures were classified into grand mal (86 cases), focal seizure (27), petit mal absence (4), psychomotro seizure (5), infantile spasms (7), and so on. It may be noted that the highest frequency of grand mal was demonstrated, while the incidences of infantile spasms, myoclonic seizure, and akinetic seizure were low in the series. Only 28 children (15.1%) had complications of physical and/or mental handicaps. The follow-up study revealed that 140 patients (75.7%) had been seizure-free in the last 12 months. One hundred and fifteen of them had no seizures for five years or longer. On the other hand, electroencephalographic abnormalities generally continued for a long time after disappearance of seizures. Eightly-one of well-controlled patients were gradually decreasing the doses of anticonvulsants. As for seizure types, it is noted that focal seizure, psychomotor seizure, and infantile spasms were relatively difficult to be controlled. Except for 27 patients, most of them attended normal schools, including junior colleges or universities, and engaged in various occupations. Fifteen female patients had already married, and out of 13 babies who were born from these patients, there were one with ventricular septal defect, one with mental deficiency, and one with anencephaly, while the rest were entirely normal. Additional problems on withdrawal of anticonvulsants after a long-term seizure-free period, and what a medical system should be for treatment of epilepsy in children up to their adulthood were discussed.
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PMID:Long-term prognosis of epilepsy in children--a follow-up report beyond 18 years of age. 99 13

A 28-year-old male of progressive myoclonus epilepsy was reported, who had showed a gradual progression in myoclonus, mental retardation and cerebellar symptoms, and had been treated with a large dosage of diphenylhydantoin. Neuropathologically, slight degenerative changes of the cerebrl cortex, especially in the IV layer, the external pallidum, and the dentate and olivary nuclei were observed. The most obvious change was diffuse reduction of Purkinje's and granular cells in the cerebellum. A congenital cyst was found with surrounding gliosis in the central tegmental tract of the pons. A significant relationship between myoclonus and the cyst was proposed, and furthermore, influences of diphenylhydantoin intoxication on the clinicopathological development of myoclonus epilepsy were emphasized.
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PMID:A neuropathological case-study of myoclonus epilepsy. 99 18

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

Two patients with mitochondrial encephalomyopathy (MEP) serve to emphasize the variability of this group of diseases. Cerebral insults, mitochondrial cardiopathy, relapsing ileus, cerebral angioma, ataxia, and myoclonic seizures characterized the first case of an adult man with similar diseases in his family, interpreted as transitional form between mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and myoclonus epilepsy associated with ragged red fibers (MERRF). The second patient, a floppy infant with cardiomyopathy and myoclonism, statomotoric and mental retardation showed combined defects in mitochondrial respiratory chain at NADH-CoQ reductase and cytochrome c oxidase and a deficiency of carnitine. In both patients neuropathologically criteria of Leigh's syndrome could be demonstrated in the cerebral cortex, in case 2 also clinically. The classificatory problems of the relationships between KSS, MELAS, MERRF, Leigh's as well as Alpers' syndromes are discussed.
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PMID:Mitochondrial myopathies with necrotizing encephalopathy of the Leigh type. 322 73

Thirty children (20 males, 10 females) with intractable epilepsy received vigabatrin (VGB) as an open label basis to preexisting antiepileptic drugs. The seizure types consisted of generalized tonic clonic seizure [10], complex partial seizure [8], myoclonic seizure [7], and mixed type with simple partial seizure, complex partial seizure and/or generalized seizure [5]. The cause of the epilepsy was cryptogenic in 16 and symptomatic in 12. The current dosage regime of anticonvulsants were maintained during the trial period. VGB at 40-80 mg/kg/day were titrated according to the clinical response for a period of 2-24 months. The result of treatment was categorized as 'responders' with 13 (43%) having 50-75% reduction of seizure frequency; and 'non-responders' which consisted of 17 children. There was no relationship between outcome of VBG add-on therapy and the sex, age of onset, type of seizure, type of epileptic syndrome, etiology, associated neurological abnormality, mental retardation or abnormal brain CT/MRI findings.
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PMID:Open label trial with vigabatrin in children with intractable epilepsy. 750 85

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

A new autosomal recessively inherited disease of the central nervous system involving childhood epilepsy and mental deterioration is described. Twenty three patients (11 males and 12 females) belonging to 11 families from northern Finland have been identified. A common ancestor has been found for nine families. The mean age of onset of epilepsy was 6.7 years (range 5-10 years) and the epilepsy was characterised by generalised tonic-clonic seizures increasing in frequency up to puberty. One third of the patients also had complex partial seizures during childhood. During young adulthood the epileptic activity began to decrease, but complete remission did not occur. Electroencephalography showed progressive slowing of the background activity with relatively scanty epileptiform activity. Out of four ictal recordings the paroxysmal activity was initiated focally in two cases. Clonazepam and sodium valproate had some antiepileptic effect, clonazepam being the more beneficial of the two. Mental development, which was originally normal, began to deteriorate two to five years after the onset of epilepsy, and the deterioration continued during adulthood in spite of good epilepsy control, leading to mental retardation by middle age. The pathogenesis of the disorder, called the Northern epilepsy syndrome, is unknown. Linkage analysis using DNA markers linked to the EPM1 gene for progressive myoclonus epilepsy of Unverricht-Lundborg type showed that the Northern epilepsy syndrome is not allelic to EPM1.
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PMID:Northern epilepsy syndrome: an inherited childhood onset epilepsy with associated mental deterioration. 801 63

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

Inherited mutations in the cystatin B gene ( CSTB ) are responsible for progressive myoclonus epilepsy type 1 (EPM1; MIM 254800). This autosomal recessive disease is characterized by variable progression to mental retardation, dementia and ataxia. The majority of EPM1 alleles identified to date contain expansions of a dodecamer repeat located upstream of the transcription start site of the CSTB gene. Normal alleles contain two or three copies of the repeat, whereas pathogenic alleles contain >40 repeats. We examined the meiotic stability of pathogenic, expanded EPM1 alleles from 17 EPM1 families by employing a fluorescence-based PCR-based genotyping assay capable of detecting single dodecamer repeat unit differences on an automated DNA sequencer. We followed 74 expanded allele transmissions to 30 affected individuals and 22 carriers. Thirty-five of 74 expanded allele transmissions demonstrated either contraction or expansion of the minisatellite, typically by a single repeat unit. Thus expanded alleles of the EPM1 minisatellite demonstrate a mutation rate of 47%, the highest yet observed for pathogenetic alleles of a human minisatellite.
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PMID:Instability of the EPM1 minisatellite. 1048 66


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