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)

Sarcosinemia has been detected by routine screening of urine for metabolic and transport disorders in Massachusetts. Three infants who had sarcosinemia were detected through the neonatal urine specimen, an observed incidence of 1:350,000. A fourth child had sarcosinemia detected through family screening after his brother was found to have Hartnup disease by neonatal urine screening. These four children with sarcosinemia have plasma sarcosine concentrations ranging from 80 to 603 mumol/L and urine sarcosine from 2.1 to 9.4 mumol/mg of creatinine, findings similar to those reported for persons with sarcosinemia. No treatment has been given. At 3.8 to 15 years of age, the children had normal findings on physical examination and had no specific illnesses. Their full-scale IQ scores ranged from 89 to 111. The oldest child had a learning and emotional disorder, and one other child was emotionally unstable. It was concluded that sarcosinemia as a specific disorder is probably benign and that the mental retardation and dysmorphic features described in some affected persons are likely coincidental with the biochemical defect. The emotional disturbances that were encountered in two children are also probably coincidental but need further attention in this disorder.
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PMID:Massachusetts Metabolic Disorders Screening Program: III. Sarcosinemia. 620 80

Sarcosine dehydrogenase is a liver mitochondrial matrix flavoenzyme that is defective in patients with sarcosinemia, a rare autosomal metabolic defect characterized by elevated levels of sarcosine in blood and urine. Some patients also exhibit mental retardation and growth failure. A full-length cDNA for human sarcosine dehydrogenase was isolated from an adult liver cDNA library. The first 22 residues in the deduced amino acid sequence exhibit features expected for a mitochondrial targeting sequence. The predicted mass of the mature human liver sarcosine dehydrogenase (99,505 Da) is in good agreement with that observed for rat liver sarcosine dehydrogenase ( approximately 100,000 Da). Human sarcosine dehydrogenase exhibits 89% identity with rat liver sarcosine dehydrogenase and strong homology ( approximately 35% identity) with rat liver dimethylglycine dehydrogenase, a sarcosine dehydrogenase-related protein from Rhodobacter capsulatus, and the regulatory subunit from bovine pyruvate dehydrogenase phosphatase. The human sarcosine dehydrogenase gene is at least 75.3 kb long and located on chromosome 9q34. The adult human liver clone is assembled from 21 exons (1-6, 7a, 8a, 9-21). Two smaller cDNA clones, isolated from adult liver and infant brain libraries, were assembled from the same sarcosine dehydrogenase gene by the use of alternate polyadenylation and splice sites. This is the first report of the genomic structure of the sarcosine dehydrogenase gene in any species. The observed chromosomal location is consistent with genetic studies with a mouse model for sarcosinemia that map the mouse gene to a region of mouse chromosome 2 syntenic with human 9q33-q34. The availability of the SDH gene sequence will enable characterization of the genotypes of sarcosinemia patients with different phenotypes.
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PMID:Cloning and mapping of the cDNA for human sarcosine dehydrogenase, a flavoenzyme defective in patients with sarcosinemia. 1044 31

Sarcosine is an N-methyl derivative of the amino acid glycine, and its elevation in tissues and physiological fluids of patients with sarcosinemia could reflect a deficient pool size of activated 1-carbon units. Sarcosinemia is a rare inherited metabolic condition associated with mental retardation. In the present study, we investigated the acute effect of sarcosine and/or creatine plus pyruvate on some parameters of oxidative stress and energy metabolism in cerebral cortex homogenates of 21-day-old Wistar rats. Acute administration of sarcosine induced oxidative stress and diminished the activities of adenylate kinase, GAPDH, complex IV, and mitochondrial and cytosolic creatine kinase. On the other hand, succinate dehydrogenase activity was enhanced in cerebral cortex of rats. Moreover, total sulfhydryl content was significantly diminished, while DCFH oxidation, TBARS content, and activities of SOD and GPx were significantly enhanced by acute administration of sarcosine. Co-administration of creatine plus pyruvate was effective in the prevention of alterations provoked by sarcosine administration on the oxidative stress and the enzymes of phosphoryltransfer network. These results indicate that acute administration of sarcosine may stimulate oxidative stress and alter the energy metabolism in cerebral cortex of rats. In case these effects also occur in humans, they may contribute, along with other mechanisms, to the neurological dysfunction of sarcosinemia, and creatine and pyruvate supplementation could be beneficial to the patients.
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PMID:Evaluation of Oxidative Stress Parameters and Energy Metabolism in Cerebral Cortex of Rats Subjected to Sarcosine Administration. 2735 17