Long-term follow-up of Taiwanese Chinese patients treated early for 6-pyruvoyl-tetrahydropterin synthase deficiency

Arch Neurol. 2008 Mar;65(3):387-92. doi: 10.1001/archneur.65.3.387.

Abstract

Objective: To report the long-term results of early initiation of treatment of 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency.

Design: Between 1988 and 2000, 12 newborns with PTPS deficiency who underwent early treatment at our hospital were identified. All patients received tetrahydrobiopterin replacement in a daily dosage between approximately 2 and 4 mg/kg. The dosages of levodopa replacement were 10 to 15 mg/kg/d, which is considerably higher than the typically recommended dosages of less than 7 mg/kg/d for patients aged younger than 2 years and 8 to 10 mg/kg/d for patients aged 2 years or older. Replacement with 5-hydroxytryptophan varied widely among patients.

Setting: Taipei Veterans General Hospital. Patients Twelve newborns.

Interventions: Treatment with tetrahydrobiopterin, levodopa, and 5-hydroxytryptophan. Main Outcome Measure IQ score.

Results: The mean (SD) IQ score of our PTPS-deficient patients was 96.7 (9.7; range 86-119), which is considerably higher than previous reports of other populations of PTPS-deficient patients. All patients reached a normal IQ on high daily dosages of levodopa replacement, without developing apparent long-term levodopa-induced adverse effects. We also observed a correlation between long-term IQ score and genotype, birth weight, and age at initiation of treatment.

Conclusions: An effective newborn screening referral program and early initiation of appropriate therapy preserved the IQ scores of PTPS-deficient patients.

Publication types

  • Clinical Trial

MeSH terms

  • 5-Hydroxytryptophan / therapeutic use*
  • Adolescent
  • Adult
  • Asians / ethnology
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Intelligence / drug effects
  • Intelligence Tests
  • Levodopa / therapeutic use*
  • Longitudinal Studies
  • Male
  • Phenylketonurias / blood
  • Phenylketonurias / drug therapy*
  • Phosphorus-Oxygen Lyases / deficiency*
  • Pterins / therapeutic use*
  • Retrospective Studies
  • Statistics, Nonparametric
  • Taiwan
  • Time Factors

Substances

  • Pterins
  • tetrahydropterin
  • Levodopa
  • 5-Hydroxytryptophan
  • Phosphorus-Oxygen Lyases
  • 6-pyruvoyltetrahydropterin synthase