Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a 19-year-old white male with juvenile galactosialidosis. He presented with hip arthralgia and was found to have facial "coarseness," corneal clouding, mitral and aortic insufficiency, and hepatosplenomegaly. Ultrastructural studies of skin biopsy and peripheral blood lymphocytes showed membrane-bound inclusions containing sparse fibrillogranular material. Biochemical analysis showed elevated urinary sialyloligosaccharides and no free sialic acid. Fibroblast enzyme analysis showed low activities of both alpha-neuraminidase and beta-galactosidase. To date, most patients with juvenile galactosialidosis have been Japanese. However, unlike those patients, our patient did not have macular cherry-red spots, neurologic abnormalities, or mental retardation. We speculate that this young man represents a new subtype of juvenile galactosialidosis with a potentially different molecular defect from that of the Japanese variant.
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PMID:Juvenile galactosialidosis in a white male: a new variant. 314 49

Dutch type periodic fever (DPF) is an autosomal recessive hereditary fever syndrome. Cases have been reported worldwide, the majority from France and The Netherlands. From infancy the patients suffer fever attacks that recur every 2-8 weeks, often precipitated by immunizations, infections or emotional stress. Fever lasts 2-7 days and can be accompanied by malaise, headache, diarrhea, abdominal pain, vomiting, skin rashes, arthralgia, arthritis, tender lymphadenopathy, hepatosplenomegaly, and oral and genital ulcers. Laboratory evaluation during fever shows granulocytosis and elevated acute phase reactants. DPF is caused by a deficiency of the enzyme mevalonate kinase (MK). Besides DPF, the spectrum of MK deficiency includes a severe phenotype, mevalonic aciduria (MA). MA patients have less residual MK activity, leading to substantially higher urinary mevalonic acid excretion than in DPF. Mevalonic aciduria is characterized by mental retardation and dysmorphic features in addition to the clinical features of DPF. At the genomic level, several mutations of varying severity have been identified. The DPF phenotype is caused by one particular mild missense mutation. Most patients are compound heterozygotes for this mutation and a more severe mutation. The mechanism by which MK deficiency leads to fever is not understood. The vast majority of DPF patients have persistently elevated serum IgD and can be classified as having hyperimmunoglobulinemia D and periodic fever syndrome (HIDS). Conversely, most HIDS patients have MK deficiency and hence DPF, but the two disorders do not overlap entirely.
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PMID:Mevalonate kinase deficiency and Dutch type periodic fever. 1094 35

Mevalonic aciduria (MVA) and hyperimmunoglobulinemia D syndrome (HIDS) represent the two ends of a clinical spectrum of disease caused by deficiency of mevalonate kinase (MVK), the first committed enzyme of cholesterol biosynthesis. At least 30 patients with MVA and 180 patients with HIDS have been reported worldwide. MVA is characterized by psychomotor retardation, failure to thrive, progressive cerebellar ataxia, dysmorphic features, progressive visual impairment and recurrent febrile crises. The febrile episodes are commonly accompanied by hepatosplenomegaly, lymphadenopathy, abdominal symptoms, arthralgia and skin rashes. Life expectancy is often compromised. In HIDS, only febrile attacks are present, but a subgroup of patients may also develop neurological abnormalities of varying degree such as mental retardation, ataxia, ocular symptoms and epilepsy. A reduced activity of MVK and pathogenic mutations in the MVK gene have been demonstrated as the common genetic basis in both disorders. In MVA, the diagnosis is established by detection of highly elevated levels of mevalonic acid excreted in urine. Increased levels of immunoglobulin D (IgD) and, in most patients of immunoglobulin A (IgA), in combination with enhanced excretion of mevalonic acid provide strong evidence for HIDS. The diagnosis is confirmed by low activity of mevalonate kinase or by demonstration of disease-causing mutations. Genetic counseling should be offered to families at risk. There is no established successful treatment for MVA. Simvastatin, an inhibitor of HMG-CoA reductase, and anakinra have been shown to have beneficial effect in HIDS.
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PMID:Mevalonate kinase deficiencies: from mevalonic aciduria to hyperimmunoglobulinemia D syndrome. 1672 36