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)

Argininosuccinic aciduria (ASA-uria) is a rare inborn error of the urea cycle, in which there is massive excretion of argininosuccinic acid (ASA) in the urine together with elevated concentrations of ASA in the plasma and the CSF. The characteristic symptoms are either those of overwhelming metabolic disease in the newborn period, or variable psychomotor retardation. The present patient, the first Finnish one to be reported, was a 49-year-old woman. She was hospitalized at the age of 26 with a diagnosis schizophrenia and mental retardation. Her clinical symptoms consisted of ataxia, disturbance of coordination, clumsiness, intention treMor and a positive Romberg's sign. The laboratory findings were consistent with the mild, late-onset type of ASA-uria.
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PMID:Argininosuccinic aciduria in a Finnish woman presenting with psychosis and mental retardation. 713 86

Argininosuccinicaciduria is a rare metabolic disorder of the urea cycle associated with the inability to excrete nitrogenous waste in the form of urea. Along with low serum arginine, hepatomegaly, and mental retardation, congenital trichorrhexis nodosa is a distinguishing feature of the disorder. We present a 3.5-year-old girl diagnosed with argininosuccinicaciduria who presented to the dermatology clinic with hair thinning and loss since birth. Microscopic evaluation revealed nodular swellings on the hair shafts and frayed cortical fibers consistent with the diagnosis of trichorrhexis nodosa occurring in the setting of argininosuccinicaciduria.
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PMID:Trichorrhexis nodosa secondary to argininosuccinicaciduria. 1730 Jun 44

Adenylosuccinate lyase (ASL), a catalyst of key reactions in purine biosynthesis, is normally a homotetramer in which three subunits contribute to each of four active sites. Human ASL deficiency is an inherited metabolic disease associated with autism and mental retardation. We have characterized five disease-associated ASL mutants: R194C and K246E are located at subunit interfaces, L311V is in the central helical region away from the active site, and R396C and R396H are at the entrance to the active site. The V(max) (at 25 degrees C) for R194C is comparable to that of WT, while those of L311V, R396C, R396H, and K246E are considerably reduced and affinity for adenylosuccinate is retained. The mutant enzymes have decreased positive cooperativity as compared to WT. K246E exists mainly as dimer or monomer, accounting for its negligible activity, whereas the other mutant enzymes are similar to WT in the predominance of tetramer. At 37 degrees C, the specific activity of WT and these mutant enzymes slowly decreases 30-40% with time and reaches a limiting specific activity without changing significantly the amount of tetramer. Mutant R194C is unique in being rapidly inactivated at the harsher temperature of 60 degrees C, indicating that it is the least stable enzyme in vitro. Conformational changes in the mutant enzymes are evident from protein fluorescence intensity at 25 degrees C and after incubation at 37 degrees C, which correlates with the loss of enzymatic activity. Thus, these disease-associated single mutations can yield enzyme with reduced activity either by affecting the active site or by perturbing the enzyme's structure and/or native conformation which are required for catalytic function.
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PMID:Biochemical and biophysical analysis of five disease-associated human adenylosuccinate lyase mutants. 1940 74