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)

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

Defects of neuraminidase activities towards sialyloligosaccharides in fibroblasts and leucocytes and enhanced excretion of sialyloligosaccharides in urine were shown in patients with adult type sialidosis with partial deficiency of beta-galactosidase and cherry red spot-myoclonus syndrome. No differences in their neuraminidase residual levels and urinary excretion patterns on thin-layer chromatography were found between these two disorders. In mucolipidosis II and III patients, the neuraminidase activities towards sialyloligosaccharides were almost normal in leucocytes, although decreased in fibroblasts. The discrepancy of neuraminidase activities towards 2 leads to 3 and 2 leads to 6 sialyloligosaccharide isomers was not noticed in all cases.
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PMID:Neuraminidase activities in sialidosis and mucolipidosis. 709 97

A macular cherry red spot is a strikingly visible abnormality indicating storage of an abnormal metabolic product by the retinal ganglion cells. The flash and pattern electroretinograms (ERG) and visual evoked potentials (VEP) of a patient with the cherry-red spot-myoclonus syndrome, a sialidosis due to neuraminidase deficiency, were studied. The flash ERG was normal but the pattern ERG had an abnormal waveform with a significantly attenuated p-q wave component. Corresponding flash VEPs were normal, but pattern VEPs were delayed. This case documents human evidence that the pattern ERG is organised in the ganglion cells whereas the flash ERG, as is well known, is generated in the distal retina.
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PMID:Abnormal pattern electroretinograms with macular cherry-red spots: evidence for selective ganglion cell damage. 730 43

A 24 year-old white male patient presents since 8 years progressive gait disturbances, myoclonic jerks and a decrease of eyesight. Clinical examination reveals features reminding of Ramsay Hunt dyssynergia cerebellaris myoclonica associated with cherry-red spots in the eyegrounds. The diagnosis of sialidosis is supported by the ultrastructural examination of skin-conjunctival biopsies and by the abnormal urinary excretion of sialyloligosaccharides. It is established by the demonstration of a deficiency of acid neuraminidase in leukocytes and cultured fibroblasts. The phenotypic spectrum of sialidosis is extremely wide; this case belongs to the cherry-red spot myoclonus syndrome (Rapin et al., 1978), also called sialidosis type 1 - normosomatic group (Lowden and O'Brien 1979).
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PMID:[A new observation of cherry-red spot myoclonus syndrome (author's transl)]. 736 41

The sialidoses are a group of storage disorders of autosomal recessive inheritance in which there is a deficiency of lysosomal neuraminidase (sialidase) activity and associated sialyloligosacchariduria. Patients with one type of sialidosis may present initially to the ophthalmologist because of a cherry-red spot at the macula. In most of these patients progressive neurologic deficits ultimately develop; myoclonus is a prominent feature. A patient with the so-called cherry-red spot--myoclonus syndrome is described who had a marked deficit of the ocular smooth pursuit system, with consequent nystagmus. His visual system was normal clinically and electrophysiologically despite the obvious storage in the retinal ganglion cells.
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PMID:Sialidosis: the cherry-red spot--myoclonus syndrome. 737 86

In order to determine what kind of voluntary movement induces action myoclonus, we gave two siblings with sialidosis two kinds of tasks. When the patients were asked to move their index fingers following a smoothly moving target, action myoclonus became prominent. In contrast, when they were asked to perform the same movements with their eyes closed, they could move their index fingers very smoothly. This shows that action myoclonus was induced by visually guided movement, but not by self-paced movement. Our observations might reflect a disorder of the cerebellum, which controls visually guided movement.
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PMID:Action myoclonus induced by visually guided movement. 813 31

The chromosomal loci for seven epilepsy genes have been identified in chromosomes 1q, 6p, 8q, 16p, 20q, 21q, and 22q. In 1987, the first epilepsy locus was mapped in a common benign idiopathic generalized epilepsy syndrome, juvenile myoclonic epilepsy (JME). Properdin factor or Bf, human leukocyte antigen (HLA), and DNA markers in the HLA-DQ region were genetically linked to JME and the locus, named EJM1, was assigned to the short arm of chromosome 6. Our latest studies, as well as those by Whitehouse et al., show that not all families with JME have their genetic locus in chromosome 6p, and that childhood absence epilepsy does not map to the same EJM1 locus. Recent results, therefore, favor genetic heterogeneity for JME and for the common idiopathic generalized epilepsies. Heterogeneity also exists in benign familial neonatal convulsions, a rare form of idiopathic generalized epilepsy. Two loci are now recognized; one in chromosome 20q (EBN1) and another in chromosome 8q. Heterogeneity also exists for the broad group of debilitating and often fatal progressive myoclonus epilepsies (PME). The gene locus (EPM1) for both the Baltic and Mediterranean types of PME or Unverricht-Lundborg disease is the same and is located in the long arm of chromosome 21. Lafora type of PME does not map to the same EPM1 locus in chromosome 21. PME can be caused by the juvenile type of Gaucher's disease, which maps to chromosome 1q, by the juvenile type of neuronal ceroid lipofuscinoses (CLN3), which maps to chromosome 16p, and by the "cherry-red-spot-myoclonus" syndrome of Guazzi or sialidosis type I, which has been localized to chromosome 10. A point mutation in the mitochondrial tRNA(Lys) coding gene can also cause PME in children and adults (MERFF).
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PMID:Progress in mapping human epilepsy genes. 829 22

Cases of two Japanese siblings with adult-onset sialidosis type I are reported. A 38-year-old man had gradually developed involuntary movement of the extremities from the age of 31. On admission, he had no skeletal abnormalities and hepatosplenomegaly, but showed myoclonus of the extremities and dyskinesia in the perioral region. We found cherry-red spots and a giant potential in a somatosensory evoked potential (SEP) study. Then, the diagnosis of sialidosis type I was confirmed by low activity of white blood cell sialidase. MRI (SE, TR 2,000/TE 100, 40) of the brain revealed a small high intensity are in the cerebral white matter adjacent to the posterior horn of the right cerebral ventricle. To our knowledge, no report on MRI findings of the brain in sialidosis type I has been reported. So far, it is uncertain whether or not such a lesion is caused by sialidosis. He was treated with clonazepam, sodium valproate, diphenylhydantoin, or haloperidol. The former two improved the symptoms, but SEP findings did not change. The subject's 43-year-old brother had also myoclonus and epilepsy since the age of 31, and low activity of sialidase. Their mother had no symptoms, but her sialidase activity level was as low as that of a carrier. These two are the eighth and ninth cases of sialidosis type I in Japan to be confirmed by enzyme activity.
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PMID:[Two siblings with adult-onset sialidosis type I (cherry-red spot-myoclonus syndrome)]. 877 7

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

Two cases of non-immunological hydrops fetalis (NIHF) presenting with massive ascites are reported; in both patients an oligosaccharid-pattern in the urine typical for sialidosis resp. galactosialidosis was found. The cerebral sonography of both patients showed streaky echo enhancement in the region of the thalamostriatal vessels, which was interpreted as calcification of the vessels. The courses of the patients were characterised by recurrent infections, hepatosplenomegaly and myoclonus. Relevant literature reports on a large variability in the clinical appearance of oligosaccharidoses. The diagnosis of sialidosis is confirmed in cultured fibroblasts by the deficiency of alpha-N-acetylneuraminidase and, in case of galactosialidosis by the additional lack of beta-galactosidase. The precise diagnosis in NIHF is of increasing interest for prenatal diagnostic as well as for neonatological management.
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PMID:[Sialidosis and galactosialidosis as the cause of non-immunologic hydrops fetalis]. 944 Sep 57


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