title: Lesch-Nyhan syndrome: biochemical characterization of a case with attenuated behavioral manifestation.
abstract: The activity and kinetic properties of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) were studied in fibroblasts from a Lesch-Nyhan syndrome (LNS) variant, with complete HGPRT deficiency in hemolysates, but with attenuated behavioral manifestation of the syndrome. The mutant HGPRT exhibited a 100-fold increase in Km for substrate phosphoribosyl-pyrophosphate, manifest in markedly decreased enzyme activity, being 2.5% of normal in cell extracts and about 0.6% of normal in intact cells. This degree of residual activity of the mutant enzyme is within the range found in patients with classical LNS.
mesh_terms: D000328:Adult; D002675:Child, Preschool; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006579:Heterozygote; D006801:Humans; D019271:Hypoxanthine; D007041:Hypoxanthine Phosphoribosyltransferase / Q000032:analysis* / Q000172:deficiency; D007042:Hypoxanthines / Q000378:metabolism; D007700:Kinetics; D007926:Lesch-Nyhan Syndrome / Q000201:enzymology* / Q000235:genetics / Q000523:psychology; D008297:Male; D010428:Pentosephosphates / Q000378:metabolism; D010754:Phosphoribosyl Pyrophosphate
chemical_list: D007042:Hypoxanthines; D010428:Pentosephosphates; D019271:Hypoxanthine; D010754:Phosphoribosyl Pyrophosphate; D007041:Hypoxanthine Phosphoribosyltransferase