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)

Increased amounts of free sialic acid were found in cultured fibroblasts and urine of a 4-year-7-month-old Italian boy with mental retardation, hypotonia, failure to thrive, coarse facial features, convergent strabismus, pale skin and fair hair. Ultramicroscopic examination of conjunctival and skin tissues showed a number of membrane-bound vacuoles containing low-density granular material in the cytoplasm of the fibroblasts. The clinical, biochemical and ultrastructural findings are similar to those described in Salla disease. Neuraminidase activity is normal. The molecular basis of the sialic acid storage disease is not known. Evidence for defective transport of sialic acid across the lysosomal membrane has been demonstrated in the patient's fibroblasts. It is possible that this might represent the metabolic abnormality.
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PMID:Free sialic acid storage disease. A new Italian case. 356 61

N-acetylneuraminic acid (sialic acid) storage disease is a rare autosomal recessive lysosomal disorder. Clinically two major forms exist, an infantile type with severe progression leading to early death, and a milder form (Salla disease) with a protracted course. Intermediate forms may also exist. Diagnosis rests on the determination of an excessive excretion of sialic acid in urine and concomitant storage in fibroblasts, the severe forms exhibiting the highest excretion and storage. We present clinical, morphological, and biochemical data on three non-Finnish patients with sialic acid storage disease. Patient 1 was a preterm infant with neonatal ascites, coarse face, hepatosplenomegaly, pale skin, and wispy hair. Vacuolated lymphocytes were abundant in a peripheral blood smear and he excreted large amounts of free sialic acid. High levels of free sialic acid were also found in cultured skin fibroblasts. He died at age 6 months from progressive respiratory insufficiency. Patient 2 was an 11-month-old Egyptian girl with coarse face, frequent upper respiratory tract infections, hepatosplenomegaly, and severe psycho-motor retardation. Sialic acid excretion was elevated, likewise the storage in fibroblasts. Histological investigations documented vacuolar storage in a skin biopsy and in iliac crest tissue. Patient 3 was a 16-year-old girl with slightly coarse face, severe generalized muscular hypotonia, ataxia, and kyphoscoliosis originally diagnosed as having post-partum asphyxia. She suffered progressive motor function loss and had dysarthria. Urinary sialic acid was elevated and a skin biopsy demonstrated vacuolization. The clinical variability of sialic acid storage disease is exemplified by these three cases. Simple urinary screening for free sialic acid facilitates the diagnosis. The degree of urinary excretion may indeed correlate with clinical presentation and progression.
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PMID:The spectrum of free neuraminic acid storage disease in childhood: clinical, morphological and biochemical observations in three non-Finnish patients. 872 11

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

Salla disease represents the slowly progressive adult form of the sialic acid storage diseases, a group of autosomal-recessive neurodegenerative disorders in which psychomotor development, ataxia, axial hypotonia, and spasticity in the lower limbs occur. No skeletal dysostosis or organomegaly is present, and life expectancy is normal. Short stature can also be observed. Progressive cerebral and cerebellar atrophy associated with dysmyelination and corpus callosum hypoplasia have been shown by magnetic resonance imaging studies. We report the first patient with Salla disease in whom combined growth hormone and gonadotropin deficiencies, hypothalamic pituitary in origin, have been demonstrated by neuroendocrine studies. We believe that the multiple neuroendocrine disorder may be the consequence of the abnormalities of common neuronal pathways regulating growth hormone and gonadotropin synthesis or secretion related to the brain storage of free sialic acid and/or to the neurodegenerative process occurring in Salla disease. Therefore, a complete endocrinologic evaluation of these patients is both warranted and useful.
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PMID:Multiple neuroendocrine disorder in Salla disease. 1166 56

Salla disease (SD) is a lysosomal disorder manifesting in infancy with hypotonia, nystagmus, ataxia and retarded motor development. MRI typically shows hypomyelination confined to the cerebral white matter. We describe a patient with two MRI studies in addition to repeated urine examinations. This case was problematic because the first urine examination did not show the elevation of free sialic acid typical of SD and MRI was also atypical, with abnormal signal intensity in cerebellar white matter. We recommend repeated urinary examinations and a search for SLC17A5 mutations in patients with cerebral signal intensity abnormalities typical of SD and emphasise that cerebellar white-matter involvement on MRI does not exclude the diagnosis.
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PMID:A case of Salla disease with involvement of the cerebellar white matter. 1517 31

The allelic autosomal recessive lysosomal storage disorders Salla disease and infantile free sialic acid storage disease (ISSD) result from mutations in SLC17A5. This gene codes for sialin, a lysosomal membrane protein that transports the charged sugar, N-acetylneuraminic acid (sialic acid), out of lysosomes. ISSD has a severe phenotype with infantile onset, while the Finnish variant, Salla disease, has a milder phenotype with later onset. Both disorders cause developmental delay, and ISSD is generally fatal in early childhood. We describe a 30-month old non-Finnish, Caucasian child with global developmental delay of postnatal onset, language, and motor skills stagnant at a 3-4 month level, hypotonia, and mild but progressive coarsening of facial features. Urinary excretion of free sialic acid was elevated 4.5 times above control. EM of a skin biopsy revealed enlarged secondary lysosomes consistent with oligosaccharide storage. Free sialic acid in fibroblasts was 3.8+/-0.9 nmol/mg protein (concurrent normal controls, 0.5+/-0.1); differential centrifugation indicated a lysosomal location. Genomic analysis revealed compound heterozygosity for two new SLC17A5 mutations. This child's clinical manifestations of a lysosomal free sialic acid storage disease are consistent with her sialin mutations and biochemical findings. The differential diagnosis of postnatal developmental delay should include free sialic acid storage disorders such as ISSD and Salla disease.
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PMID:Clinical, biochemical, and molecular diagnosis of a free sialic acid storage disease patient of moderate severity. 1517 1

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

Sialic acid storage disorder, known as Salla disease, is a rare autosomal recessive lysosomal disorder produced by a defect of a proton-driven carrier that is responsible for the efflux of sialic acid from the lysosomal compartment. We report two patients with Salla disease: a two-year-old girl, presented with hypotonia, inability to speak and walk, bilateral optic atrophies, defective myelination, cerebellar atrophy, and thinning of the corpus callosum on magnetic resonance imaging (MRI), who was classified as intermediate severe Salla disease; and a four-year-old girl, presented with relatively late-onset, slight hypotonia, and delayed language and mobility development, and supported by relatively protected MRI findings, who was classified as conventional Salla disease. Diagnosis of Salla disease was confirmed by accumulation of sialic acid in fibroblast culture: 15.1 and 13.2 nmol/mg protein in the first and second patient, respectively. Optic atrophy observed in the first case may be an additional feature besides the characteristic manifestations of Salla disease.
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PMID:Salla disease in Turkish children: severe and conventional type. 2019 97