title: Tetrahydrobiopterin-responsive phenylketonuria: the New South Wales experience.
abstract: Recent studies have shown that a subgroup of phenylketonuric patients respond to high doses of BH4 (20 mg/kg) by a decrease of plasma phenylalanine. A clinically significant response has been defined as a decrease in phenylalanine by more than 30% within 24 h, after a BH4 challenge. We report our experience with 37 patients diagnosed with hyperphenylalaninemia, mild, moderate, or classical Phenylketonuria (PKU) using a seven day combined BH4 and phenylalanine load. Nine of the 37 patients responded with a 30% decrease in their phenylalanine levels in the first 8 h of treatment. A total of 17 patients (46%) had a decrease of at least 30% during the study period. This study confirms that a significant number of patients with mild to moderate PKU will respond to a BH4 load. Furthermore, it confirms that the seven-day phenylalanine test is more sensitive in detecting BH4 responsive patients.
authors.affiliation: Department of Genetics, Montreal Children's Hospital, Montreal, Canada H3H 1P3. john.mitchell@muhc.mcgill.ca
authors.forename: John J
authors.initials: JJ
authors.lastname: Mitchell
authors.forename: Bridget
authors.initials: B
authors.lastname: Wilcken
authors.forename: Ian
authors.initials: I
authors.lastname: Alexander
authors.forename: Carolyn
authors.initials: C
authors.lastname: Ellaway
authors.forename: Helen
authors.initials: H
authors.lastname: O'Grady
authors.forename: Veronica
authors.initials: V
authors.lastname: Wiley
authors.forename: John
authors.initials: J
authors.lastname: Earl
authors.forename: John
authors.initials: J
authors.lastname: Christodoulou
mesh_terms: D000293:Adolescent; D001708:Biopterins / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009517:New South Wales; D010649:Phenylalanine / Q000097:blood*; D010661:Phenylketonurias / Q000097:blood / Q000188:drug therapy*
chemical_list: D001708:Biopterins; D010649:Phenylalanine; C003402:sapropterin