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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The possible associations of myoclonic phenomena, progressive or non progressive encephalopathies and epileptic phenomena are reviewed with special emphasis on childhood. This leads to the following five groups of conditions: (1) myoclonus without encephalopathy and without epilepsy; (2) encephalopathies with non-epileptic myoclonus; (3) progressive encephalopathies with myoclonic seizures or epileptic syndromes (Progressive myoclonus epilepsies); (4) epileptic encephalopathies with myoclonic seizures; (5) myoclonic epilepsies. In the first group, which also includes physiological myoclonus, a more thorough description of "benign sleep myoclonus of newborn" and "benign myoclonus of early infancy" is given. Characteristic of group 2 are "Kinsbourne syndrome" and certain types of "Hyperekplexia" which pose interesting differential diagnosis problems with stimulus-sensitive epilepsies. In group 3, the concept of progressive encephalopathies is stressed, meaning that "Progressive Myoclonus Epilepsies" are always in fact progressive encephalopathies presenting with myoclonic types of seizures or epileptic syndromes among other neurologic and psychologic signs and symptoms. Major and rare causes are reviewed. The term major is applied to typical features or to frequency, whereas rare causes include not only those what are rarely seen, but also some myoclonic variants of diseases which usually have different symptoms. The fourth group refers to severe epilepsies, mainly in infancy and childhood, which lead to mental retardation irrespective of their cause. The assumption is that diffuse and persistent epileptic activity may interfere with normal development of the higher cerebral functions. "West syndrome" and "Lennox-Gastaut syndrome" are the more representative examples and may present with myoclonic type of seizures, but they are not dealt with in detail here. Group 5 comprises true myoclonic epilepsies, differentiating syndromes recognized as idiopathic, such as "benign myoclonic epilepsy of infancy" and "juvenile myoclonic epilepsy", from those which are cryptogenic and carry a more cautious prognosis--i.e.: "cryptogenic myoclonic and myoclono-astatic epilepsies" and "Severe myoclonic epilepsy of infancy". Finally other epileptic syndromes usually not considered as myoclonic epilepsies, but presenting sometimes myoclonic seizures, are mentioned.
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PMID:[Myoclonus and epilepsies in children]. 178 Jun 7

A previously undescribed form of complicated hereditary spastic paraplegia with epileptic myoclonus in four affected offspring of consanguineous parents is reported. The disorder was inherited as an autosomal recessive trait. Age at onset varied from the prenatal period to 10 years. The main findings when examined between 26 and 42 years of age were spastic paraplegia, epileptic myoclonus, distal muscle atrophy, mental retardation or dullness, ataxia, hearing loss and a progressive course. The difference in phenotypic expression was striking. One woman had progressive epileptic myoclonus, ataxia and only slight distal wasting and could have been misdiagnosed as a case of Unverricht-Lundborg's disease. Thorough biochemical investigations revealed no cause of the disorder.
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PMID:Hereditary spastic paraplegia with epileptic myoclonus. 195 Apr 52

We reported a case of mitochondrial encephalomyopathy with repeated stroke-like episodes. A 33-year-old single male was admitted to our hospital because of stroke-like episodes with visual field defect, hemiplegia and convulsion repeated seven times for the past seven years. There were no abnormalities on the physical examination. He was hallucinative and perseverative and had mental deficiency. Muscle weakness and atrophy were not prominent, and generalized hyporeflexia were present without pathological reflexes. Myoclonus was not observed. Serum CK and blood gas analysis were normal (pH 7.398). Although blood levels of lactate and pyruvate were almost within normal limit, lactate was elevated by 20WATT-15 minutes exercises. On the contrary, the CSF levels of lactate and pyruvate were elevated markedly. CT of the brain revealed the presence of the low density areas in the right occipital and the left frontal lobes. Cranial 4 vessels studies were unremarkable. EEG showed the diffuse slowness with spike and wave complex. CT of the muscles were normal. A specimen obtained from the left biceps brachii muscle showed ragged-red fibers without obvious myogenic or neurogenic changes, and accumulations of abnormal mitochondria with paracrystalline inclusion bodies were observed by electron microscopy. However, mitochondrial abnormalities were not seen in the vessel walls in the biopsied muscle. Activities of complex I + III, II + III, IV in mitochondria were normal. Clinical features of this case were consistent with MELAS. However, this case showed no muscle weakness, short stature and lactic acidosis which characterize MELAS, and the onset of this case was later than those cases that were reported before.
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PMID:[A case of mitochondrial encephalomyopathy characterized by repeated stroke-like episodes]. 250 53

Electrophysiological investigation was performed in 3 patients with beta-galactosidase and sialidase deficiencies (sialidosis type 2) in order to elucidate the underlying mechanism of intention myoclonus. It is a rare neuronal storage disease that begins in childhood with mental retardation, skeletal abnormalities, progressive myoclonus and cherry-red spots in the macula. Electrophysiological studies showed paroxysmal activities in the EEG, consistent temporal relationship between the EEG spikes and myoclonic jerks demonstrated by jerk-locked averaging, high amplitude somatosensory evoked potentials with altered wave form, and enhanced long-loop reflexes. These results suggest that there is a hyperexcitability of the cerebral cortex, which results in induction of intention myoclonus. The intention myoclonus in sialidosis type 2 is consistent with 'cortical reflex' myoclonus described in progressive myoclonic epilepsy due to various etiologies.
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PMID:Electrophysiological studies of myoclonus in sialidosis type 2. 257 48

To study the incidence of circulating anti-CNS antibodies in childhood neurologic diseases, a population study was undertaken. Serum samples were obtained from a total of 348 children and stored at -80 degrees C until being studied. The samples were collected when routine blood tests were being performed. In all cases informed consent was obtained. This study was approved by hospital ethics review committees. One hundred and ninety-nine of the samples were from children with no known neurologic illnesses and served as the control group. One hundred and twenty-one of the samples were from children with epilepsy and the remaining 28 from a number of different neurologic conditions. The serum samples were screened against normal, adult, autopsy-derived cerebellar and frontal cortex tissue sections and Western blots. Serum immunoreactivity was revealed using HRP-conjugated anti-human IgG. Significant findings included: (1) patients with epilepsy had an increased incidence of anti-CNS reactivity as revealed on frontal cortex immunoblots (p less than 0.05) but not on cerebellar immunoblots; (2) there was an increase in the incidence of immunoblot reactivity with age in the controls and the neurology cases; (3) there was an increased incidence of immunoblot reactivity in those cases with a presumed inflammatory central or peripheral neurologic disease; (4) in six additional cases with opsoclonus-myoclonus there was cerebellar-specific immunoreactivity with identified antigenic molecular weights of 27 and 35, and 62 kDaltons; (5) in 31 additional cases of systemic lupus erythematosus there was significant immunoblot reactivity (p less than 0.001) when compared to a subset of age-matched controls. There was no difference in immunoreactivity between males and females. There was no significant increase in immunoreactivity in those children with cognitive disturbances including developmental delay and mental retardation.
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PMID:Anti-CNS antibodies in childhood neurologic diseases. 273 81

Two siblings with hyperornithinemia, hyperammonemia, and homocitrullinuria are reported. The clinical picture included protein intolerance, mental retardation, seizures, and stuporous episodes. One patient had cerebellar ataxia, myoclonus, convulsive seizure, and muscular weakness in both legs. Isolated liver mitochondria in the patient revealed that ornithine transport and citrulline synthesis were decreased, but urea cycle enzymes and ornithine aminotransferase were normal. Ornithine metabolism was decreased in cultured skin fibroblasts.
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PMID:Hyperornithinemia, hyperammonemia, and homocitrullinuria: case report and biochemical study. 367 Jun 19

The ataxia-opsoclonus-myoclonus syndrome that was well individualized by Kinsbourne is mostly observed in young children (less than three years old in 90 percent of the cases). From six personal cases, and from a review of ninety cases of the literature, the clinical and etiological features, as well as the evolution of the syndrome, are studied. Prodromes (infectious and digestive manifestations) and comportmental changes usually precede the sudden onset of the clinical triad. Neurologic complementary investigations are typically normal during the acute phase. The frequent association (46 percent of the cases) of this syndrome to a neuroblastoma (usually thoracic) makes it very particular from the etiological point of view. The evolution is identical whatever the type ("isolated" or "tumoral"). Corticotherapy (ACTH or corticoids) is efficient in 60 percent of the cases. But recurrences and cerebral sequelae (mental deficiency and speech disorders) are frequent.
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PMID:[Ataxia-opsoclonus-myoclonus syndrome]. 626 94

We studied a patient with somatic growth failure with easy fatigability, myopathy with mitochondrial abnormality, increased lactate and pyruvate in blood and CSF, mental retardation, seizure, myoclonus, deafness, cerebellar ataxia, and blindness with macular degeneration and optic atrophy. Pathologic findings included multiple brain infarctions and massive calcification in the basal ganglia. Biochemical studies of isolated mitochondria revealed decreased oxygen consumption in skeletal muscle, diaphragm, and brain, suggesting an abnormality in the respiratory chain.
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PMID:Mitochondrial encephalomyopathy with lactate-pyruvate elevation and brain infarctions. 653 55

A further patient with a presumed primary deficiency of sialidase N-acetylneuraminic acid hydrolase EC 3.2.1.18) is described. Clinically the patient falls into the sialidosis type 2 category of the recent classification of Lowden & O'Brien (1979), i.e. he manifests coarse facies, mental retardation and skeletal changes of dysostosis multiplex as well as myoclonus and a cherry-red spot at the macula. Sialidase activity in fibroblasts was 4% of control values using a methylumbelliferone substrate. The father of the patient was found to have 50% activity. Abnormal amounts of sialyloligosaccharides were found in the urine. The electrophoretic mobility of known glycosylated enzymes and proteins was found to be altered (more anodal than usual), but could be corrected by incubation of the cell extracts with bacterial neuraminidase. The relationship of the present patient to the Lowden & O'Brien classification is discussed.
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PMID:Sialidosis type 2 (acid neuraminidase deficiency): clinical and biochemical features of a further case. 677 97

We describe 2 sibs (brother and sister) with myopathy, sideroblastic anemia, lactic acidosis, mental retardation, microcephaly, high palate, high philtrum, distichiasis, and micrognathia. Very low levels of cytochromes a, b, and c were detected in the patients' muscle mitochondria. Deposition of iron within the mitochondria of bone marrow erythroblasts was observed on electron microscopy. Irregular and enlarged mitochondria with paracrystalline inclusions were also seen on electron microscopy of the patients' muscle specimen. Examination of DNA from the affected sibs showed no deletions in the mitochondrial DNA nor the mutations identified in the syndromes of mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) or myoclonus, and epilepsy associated with rugged-red fibers (MERRF). Since the parents were first cousins and 2 of 6 sibs (male and female) were affected, we suggest that the syndrome expressed by our patients represents a previously unknown autosomal recessive disorder that includes mitochondrial myopathy, lactic acidosis, and sideroblastic anemia.
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PMID:Myopathy, lactic acidosis, and sideroblastic anemia: a new syndrome. 772 39


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