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Three‐year audit of the hyperphenylalaninaemia/phenylketonuria spectrum in Victoria
Author(s) -
Boneh Avihu,
Francis Dorothy EM,
Humphrey Maureen,
Upton Helen J,
Peters Heidi L
Publication year - 2006
Publication title -
journal of paediatrics and child health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.631
H-Index - 76
eISSN - 1440-1754
pISSN - 1034-4810
DOI - 10.1111/j.1440-1754.2006.00909.x
Subject(s) - medicine , phenylalanine , phenylalanine hydroxylase , hyperphenylalaninemia , tetrahydrobiopterin , pediatrics , phenylketonurias , newborn screening , endocrinology , amino acid , biochemistry , chemistry , nitric oxide synthase , nitric oxide
Aim: To determine the prevalence, the types and severity of hyperphenylalaninaemia (including phenylketonuria (PKU)) in Victoria and to report on a new treatment modality of PKU. Methods: We reviewed the medical records of all patients diagnosed with high blood phenylalanine levels by newborn screening between November 2001 and October 2004. Results: We identified 17 newborn babies with high levels of blood phenylalanine (total samples: 190 835). Dihydrobiopterin reductase deficiency was excluded in all babies. Five babies had persistent phenylalanine levels of 200–300, and do not receive any dietary or pharmaceutical therapy. One baby was diagnosed as having pyruvoyl tetrahydro‐pterin synthase deficiency. Following reports of tetrahydrobiopterin (BH 4 )‐responsive PKU, we have performed a BH 4 load (20 mg/kg, 6R‐5,6,7,8‐tetrahydro‐ l ‐biopetrin dehydrochloride; Schricks Laboratories, Jona, Switzerland) in 10 newborn babies with PKU (one baby with a phenylalanine level of 2600 µmol/L was started on diet without prior load). Three babies had a significant response to BH 4 (>35% decrease in phenylalanine level). Protein restriction (1.2 g/kg/day) and introduction of phenylalanine‐free formula, in addition to BH 4 treatment, were necessary in one patient. The other patients maintain good metabolic control with BH 4 treatment only (at ∼11 mg/kg/day) and an intake of 2–3 g protein per day. Of the nine babies who are on a full PKU diet, three have high phenylalanine tolerance (consistently >40 mg/kg/day). Conclusion: There is a spectrum of severity of hyperphenylalaninaemia in the population. The detection of BH 4 ‐responsive PKU patients offers them a less restrictive dietary regimen and an improved quality of life, and may enable near normal life‐style in adolescence.