Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sialic acid storage diseases (SASD, MIM 269920) are autosomal recessive neurodegenerative disorders that may present as a severe infantile form (ISSD) or a slowly progressive adult form, which is prevalent in Finland (Salla disease). The main symptoms are hypotonia, cerebellar ataxia and mental retardation; visceromegaly and coarse features are also present in infantile cases. Progressive cerebellar atrophy and dysmyelination have been documented by magnetic resonance imaging (ref. 4). Enlarged lysosomes are seen on electron microscopic studies and patients excrete large amounts of free sialic acid in urine. A H+/anionic sugar symporter mechanism for sialic acid and glucuronic acid is impaired in lysosomal membranes from Salla and ISSD patients. The locus for Salla disease was assigned to a region of approximately 200 kb on chromosome 6q14-q15 in a linkage study using Finnish families. Salla disease and ISSD were further shown to be allelic disorders. A physical map with P1 and PAC clones was constructed to cover the 200-kb area flanked by the loci D6S280 and D6S1622, providing the basis for precise physical positioning of the gene. Here we describe a new gene, SLC17A5 (also known as AST), encoding a protein (sialin) with a predicted transport function that belongs to a family of anion/cation symporters (ACS). We found a homozygous SLC17A5 mutation (R39C) in five Finnish patients with Salla disease and six different SLC17A5 mutations in six ISSD patients of different ethnic origins. Our observations suggest that mutations in SLC17A5 are the primary cause of lysosomal sialic acid storage diseases.
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PMID:A new gene, encoding an anion transporter, is mutated in sialic acid storage diseases. 1058 Oct 36

The objective of this article is to describe the clinical, radiographic, and molecular genetic features of a new intermediate form of free sialic storage disease. Free sialic storage disease is a rare autosomal recessive lysosomal disorder that results from mutations in SLC17A5, a gene that codes for sialin, a lysosomal membrane sialic acid transporting protein. Infantile sialic acid storage disease has a severe phenotype, and Salla disease (Finnish variant) is generally milder in phenotype; intermediate forms have also been described. There have been few reports of magnetic resonance imaging (MRI) in the sialic acid storage disorders; leukodystrophy has been the characteristic finding, along with hypoplasia of the corpus callosum. An 8-month-old non-Finnish child presented with hypotonia and global developmental delay. Serial MRIs with magnetic resonance spectroscopy at 9 and 16 months revealed severe hypomyelination and hypogenesis of the corpus callosum. There was mild elevation of urinary sialic acid (4.5 times above normal). Electron microscopy of a skin biopsy showed lysosomal enlargement with oligosaccharide storage, and confirmatory molecular genetic testing revealed compound heterozygosity for two new SLC17A5 mutations. Free sialic storage disease of the intermediate type is an important part of the differential diagnosis of a hypotonic, delayed child with abnormal white matter on MRI. Intermediate types of free sialic acid overlap in phenotype with infantile sialic acid storage disease and the milder Salla disease and thus might be more difficult to identify clinically; the lack of Finnish ethnicity should not preclude testing for this probably under-recognized disorder. White-matter abnormalities appear to be characteristic of the entire phenotypic spectrum.
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PMID:Novel form of intermediate salla disease: clinical and neuroimaging features. 1641 76