title: Atypical phenylketonuria caused by 7, 8-dihydrobiopterin synthetase deficiency.
abstract: A patient with atypical phenylketonuria and normal liver dihydropteridine reductase and phenylalanine-4-hydroxylase activities excreted neopterin but not biopterin or dihydrobiopterin in urine. The oral administration of L-sepiapterin (1 mg/kg body weight) lowered serum-henylalanine from 17.1 to 1.1 mg/dl within 6 h. Comparable responses were observed after oral administration of L-erythro-7, 8-dihydrobiopterin or L-erythro-5, 6, 7, 8-tetrahydrobiopterin (each given in a dose of 2.5 mg/kg body weight). The results indicate a 7, 8-dihydrobiopterin synthetase deficiency in the patient.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000172:deficiency*; D001708:Biopterins / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000172:deficiency / Q000652:urine; D002675:Child, Preschool; D005260:Female; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D010649:Phenylalanine / Q000037:antagonists & inhibitors / Q000097:blood; D010661:Phenylketonurias / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism; D011621:Pteridines / Q000096:biosynthesis* / Q000627:therapeutic use; D011622:Pterins
chemical_list: D011621:Pteridines; D011622:Pterins; D001708:Biopterins; D010649:Phenylalanine; C017226:7,8-dihydrobiopterin; D006160:Guanosine Triphosphate; C016727:sepiapterin; D000429:Alcohol Oxidoreductases