Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019214 (hepatosplenomegaly)
 4,408 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Diagnosis of GM1 gangliosidosis (OMIM 230500) is usually based on the presence of physical signs of storage such as coarse facial features, corneal clouding, cherry red macula, hepatosplenomegaly and skeletal dysostosis. More rarely it can present as nonimmune hydrops. We describe a male patient with GM1 gangliosidosis born to healthy first-cousin parents of Indian Asian descent. The disease was recognized on the basis of diffuse vacuolization of cyto- and syncytiotrophoblasts, stromal cells and amniocytes on histological analysis of the placenta. The placental examination was prompted by the prenatal detection of intrauterine growth retardation (IUGR) and oligohydramnios at 32 weeks of gestation. The diagnosis of GM1 gangliosidosis was supported by both biochemical and molecular data. The beta-galactosidase enzymatic activity on leukocytes was severely reduced, while the neuraminidase activity on fibroblasts was normal, thereby excluding galactosialidosis. The molecular analysis of the beta-galactosidase gene (GLB1) revealed a previously unreported splicing mutation (IVS1+2 insT) in homozygous state. Our case further illustrates the value of histological examination of the placenta in the diagnosis of lysosomal storage disorders and shows that either hydrops or IUGR can be presenting features of GM1 gangliosidosis in the neonatal period.
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PMID:Intrauterine growth retardation and placental vacuolization as presenting features in a case of GM1 gangliosidosis. 1771 6

Sialidosis is an autosomal recessive lysosomal storage disease caused by pathogenic variants in NEU1 which encodes lysosomal sialidase (neuraminidase 1). Lysosomal neuraminidase catalyzes the removal of terminal sialic acid molecules from glycolipids, glycoproteins and oligosaccharides. Sialidosis is classified into two types, based on phenotype and age of onset. Patients with the milder type 1 typically present late, usually in the second or third decade, with myoclonus, ataxia and visual defects. Type 2 is more severe and presents earlier with coarse facial features, developmental delay, hepatosplenomegaly and dysostosis multiplex. Presentation and severity of the disease are related to whether lysosomal sialidase is inactive or there is some residual activity. Diagnosis is suspected based on clinical features and increased urinary bound sialic acid excretion and confirmed by genetic testing showing pathogenic variants in NEU1. We report a patient with type 1 sialidosis who presented mainly with ataxia and both generalized and myoclonic seizures but no visual involvement. Whole exome sequencing of the proband detected compound heterozygous likely pathogenic variants (S182G and G227R) in NEU1.
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PMID:Type 1 sialidosis presenting with ataxia, seizures and myoclonus with no visual involvement. 3002 83


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