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

Observations have been made on two brothers who had progressive ataxia, intention myoclonus and visual failure starting early in the third decade of life. Their parents were consanguineous. The brothers showed bilateral cherry red spots at the maculae and bilateral perinuclear cataracts; their intelligence was preserved. Urine was found to contain large amounts of sialylated oligosaccharides; cultured skin fibroblasts showed deficiency of the enzyme sialidase (neuraminidase). Studies on leucocytes and cultured skin fibroblasts showed aberrant electrophoretic mobilities of six enzymes all of which are known to be glycoproteins, and this has been attributed to excessive amounts of sialic acid on the enzyme molecules. The clinical features together with the biochemical findings indicate that these are further cases of the newly described condition Sialidosis Type 1 and it is suggested that the electrophoretic findings might be typical of the condition.
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PMID:Sialidosis type 1: cherry red spot-myoclonus syndrome with sialidase deficiency and altered electrophoretic mobility of some enzymes known to be glycoproteins. II. Enzymes studies. 49 93

A family is described with three affected brothers, two of whom were examined, born to consanguineous parent, who in early adult life began to experience ataxia, intention myoclonus, and progressive visual failure. The brothers examined had cherry red spots at the maculae and cataracts. They were of normal intelligence. The intention myoclonus responded partially to treatment with clonazepam and pheneturide, but not to 5-hydroxytryptophan in combination with carbidopa or to sodium valproate. Studies in one patient showed the excretion of large quantities of sialylated oligosaccharides in the urine. Both patients showed deficient sialidase activity in their cultured fibroblasts. Further studies on cultured skin fibroblasts revealed increased electrophoretic mobility of six glycoprotein enzymes that was returned approximately to normal by treatment with sialidase. The clinical and biochemical findings indicate that these patients are further cases of the newly described condition sialidosis type 1.
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PMID:Sialidosis type 1: cherry red spot-myoclonus syndrome with sialidase deficiency and altered electrophoretic mobilities of some enzymes known to be glycoproteins. 1. Clinical findings. 51 62

Homogenates of cultured skin fibroblasts from a non-ambulatory, 20-year-old male with cherry-red spots, corneal clouding, seizures, mental retardation, dysostosis multiplex, dwarfism, coarse facies and loss of vision, originally described by Goldberg et al. (1971), have diminished neuraminidase activity and an excess of neuraminic acid-rich compounds. Specifically, these cells have 2-17% normal neuraminidase when measured with 2-(3' methoxyphenyl)-N-acetyl-alpha-neuraminic acid, N-acetyl-neuramin-lactose and fetuin. Activities of 12 other lysosomal enzymes were either at or above the range of normal control fibroblasts. Total neuraminic acid concentration was 44.3 nmol/mg protein versus an average control value of 14.2. It is concluded that the Goldberg syndrome should be considered, along with mucolipidosis I and the cherry-red spot -- myoclonus syndrome, as resulting from a primary neuraminidase deficiency.
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PMID:Neuraminidase deficiency in the original patient with the Goldberg syndrome. 51 4

The authors report the clinical criteria for the diagnosis of progressive myoclonus epilepsies on the basis of their experience following 34 cases (2 with sialidosis, 2 with MERRF, 4 with Lafora disease, 24 with Unverricht-Lundborg type, 4 with ataxic myoclonus). 3 rare forms of PME are also reported: a case of lipoma and PME, a family with dentato-rubro-pallido-luysian atrophy and a family of myoclonus epilepsy, Hartung type. The autonomy of Ramsay Hunt syndrome is discussed on the light of recent molecular genetic data.
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PMID:Progressive myoclonus epilepsies. Criteria for diagnosis on the basis of the follow-up of 37 cases. 129 89

The authors report the sequence of the clinical symptoms in type I sialidosis or cherry-red spot myoclonus syndrome, derived from the cases personally observed and from the literature. They also report neuropathological and neurochemical data. A serial EEG study in a case shows the tendency to a progressive deregulation of cerebral electric activity. Therapeutic attempts to reduce myoclonus, which is one of the more disabling symptoms in this syndrome, are described.
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PMID:Cherry-red spot myoclonus syndrome (type I sialidosis). 181 38

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

Histological and ultrastructural findings observed throughout the nervous system and the extranervous organs in a case of sialidosis type I, also known as normosomatic group, are reported. The patient was a 22-year-old male with non-familial progressive myoclonus, macular cherry-red spot, moderate cerebellar syndrome and normal intelligence. Biochemical study showed an alpha-N-acetylneuraminidase deficiency in cultured fibroblasts. A complete and early autopsy was performed. Neuropathological study showed two prominent lesions: the first one was a fine cytoplasmatic vacuolation in several neurons of the cortex, basal ganglia and thalamus and the second one was a diffuse neuronal intracytoplasmic storage of lipofuscin-like pigment (LLP). As for the extranervous organs the main light and electron microscope findings were observed in the hepatocytes and in the Kupffer's cells, which showed an enlarged cytoplasm and lipopigment granules in different amount. Vacuoles containing dense lamellar bodies were found in tubular epithelial cells of the kidney. To our knowledge this is the first complete autoptic study of a case of sialidosis type I.
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PMID:Sialidosis type I: pathological study in an adult. 262 Apr 79

Genetic storage diseases with prominent myoclonus include classic infantile Tay-Sachs disease and juvenile neuropathic Gaucher's disease among the sphingolipidoses, most of the variants of the sialidoses and ceroid-lipofuscinoses, and Lafora disease. The character of the myoclonus differs from disease to disease and often changes as the disease runs its course. For example, massive myoclonic jerks to sound with rapid habituation and a prolonged refractory period are characteristic of the early stages of Tay-Sachs disease; children with late infantile ceroid-lipofuscinosis are most sensitive to light flashes below 3 Hz, those with juvenile Gaucher's disease at 6 to 10 Hz, and those with Lafora disease at 15 to 20 Hz, whereas young adults with sialidosis are not sensitive to either light or sound but are highly sensitive to somatosensory stimulation and movement. Some patients with sialidosis were found to have two distinct types of myoclonus: (a) a stimulus-insensitive facial myoclonus without EEG correlate that persisted in slow-wave sleep and (b) stimulus-sensitive massive jerks associated with vertex positive EEG spikes on which sleep had the paradoxic effect of suppressing jerks while stimulating spikes. Systematic EEG and event-related potential studies, including backward averaging from jerks and detailed anatomic studies of postmortem specimens with modern histochemical techniques, may help illuminate these intriguing differences. New modalities are needed to treat the myoclonus of these diseases since it generally responds poorly to currently available pharmacologic agents.
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PMID:Myoclonus in neuronal storage and Lafora diseases. 308 Aug 54

A 12 year old boy with neuraminidase deficiency (sialidosis, mucolipidosis I) is described. His clinical features included coarse facies, cherry red spot, ataxia, myoclonus, and dysotosis multiplex. The level of neuraminidase activity in cultured fibroblasts was very low and intermediate levels were observed in both parents. The clinical disorders associated with neuraminidase deficiency are reviewed.
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PMID:Neuraminidase deficiency: case report and review of the phenotype. 358 42

Clinical and biochemical findings in two siblings (24-year-old sister and 20-year-old brother), born to consanguineous parents, are described. Both showed progressive generalized myoclonus, macular cherry-red spots, moderate cerebellar ataxia, coarse facies, vertebral deformities, vacuolation of peripheral lymphocytes, bone marrow cells and epithelial cells of conjunctiva, but had normal intelligence. The excretion of sialyloligosaccharides in the urine of both was 3-5 times larger than in the controls. The activities of alpha-neuraminidase and beta-galactosidase in leukocytes and cultured skin fibroblasts were reduced. The clinical and biochemical findings were those of the newly described condition, sialidosis type 2. Review of all Japanese cases considered as sialidosis type 2 showed that the most characteristic clinical features as distinct from type 1, were coarse facies and bone deformities, especially of vertebral bodies.
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PMID:Sialidosis type 2 in Japan. Clinical study in two siblings' cases and review of literature. 640 17


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