title: Dihydropteridine reductase deficiency: non-response to oral tetrahydrobiopterin load test.
abstract: In a child with dihydropteridine reductase deficiency (McKusick 26163) none of four separate oral tetrahydrobiopterin loading tests resulted in a decrease of the serum phenylalanine concentration. This test cannot be recommended for screening hyperphenylalaninaemic patients for dihydropteridine reductase deficiency.
mesh_terms: D001708:Biopterins / Q000031:analogs & derivatives; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007223:Infant; D008214:Lymphocytes / Q000201:enzymology; D009247:NADH, NADPH Oxidoreductases / Q000172:deficiency*; D010649:Phenylalanine / Q000097:blood; D010661:Phenylketonurias; D011621:Pteridines; D014443:Tyrosine / Q000097:blood
chemical_list: D011621:Pteridines; D001708:Biopterins; D014443:Tyrosine; D010649:Phenylalanine; D009247:NADH, NADPH Oxidoreductases; C003402:sapropterin