title: Tetrahydrobiopterin therapy for phenylketonuria in infants and young children.
abstract: OBJECTIVE
  To describe patient selection, treatment administration, response evaluation, and side effect management associated with sapropterin therapy in infants and children aged <4 years.
  
  
  METHODS
  Six case reports are presented from 4 US metabolic clinics treating phenylketonuria with sapropterin in patients aged 7 months to 4 years. Outcomes included blood phenylalanine (Phe) levels before and during treatment. For 3 of 6 cases, diet records were used to monitor changes in dietary Phe.
  
  
  RESULTS
  Severity of phenylketonuria ranged from mild to severe (classic). Treatment with sapropterin was safe and generally well tolerated. Blood Phe levels were reduced, or maximum dietary Phe tolerance was increased in patients with blood Phe that was well controlled by diet.
  
  
  CONCLUSIONS
  Given the increasing evidence that maintaining blood Phe levels below 360 μmol/L is important for the normal development of neurocognitive and behavioral function, sapropterin can be combined with a Phe-restricted diet to control blood Phe levels in young patients responsive to sapropterin therapy.
authors.affiliation: Department of Pediatrics, Northwestern University Feinberg School of Medicine and PKU Clinic, Children's Memorial Hospital, Chicago, IL 60614-3363, USA. bburton@childrensmemorial.org
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Burton
authors.forename: Darius J
authors.initials: DJ
authors.lastname: Adams
authors.forename: Dorothy K
authors.initials: DK
authors.lastname: Grange
authors.forename: John I
authors.initials: JI
authors.lastname: Malone
authors.forename: Elaina
authors.initials: E
authors.lastname: Jurecki
authors.forename: Heather
authors.initials: H
authors.lastname: Bausell
authors.forename: Kayt D
authors.initials: KD
authors.lastname: Marra
authors.forename: Laurie
authors.initials: L
authors.lastname: Sprietsma
authors.forename: Kathleen T
authors.initials: KT
authors.lastname: Swan
mesh_terms: D001708:Biopterins / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018579:Patient Selection; D010649:Phenylalanine / Q000097:blood; D010661:Phenylketonurias / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D001708:Biopterins; D010649:Phenylalanine; C003402:sapropterin