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Cognitive functions in patients with phenylketonuria in long-term treatment with tetrahydrobiopterin

R Gassió1, M A Vilaseca, N Lambruschini

  • 1Neuropediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Spain. rgassio@hsjdbcn.org

Molecular Genetics and Metabolism
|February 4, 2010
PubMed

Insights

Tetrahydrobiopterin (BH4) treatment in phenylketonuria (PKU) patients showed normal intelligence but fine motor impairments. No significant difference in motor function was observed compared to dietary treatment, warranting further research.

Area of Science:

  • Neuroscience
  • Metabolic Disorders
  • Genetics

Background:

  • Phenylketonuria (PKU) is a genetic disorder requiring lifelong management.
  • Tetrahydrobiopterin (BH4) is a cofactor used in treating PKU.
  • Long-term effects of BH4 on cognitive function in PKU require further investigation.

Purpose of the Study:

  • To assess cognitive functions in pediatric PKU patients undergoing long-term BH4 treatment.
  • To compare cognitive outcomes in BH4-treated PKU patients with those on dietary management.

Main Methods:

  • Cognitive functions (IQ, visuospatial, memory, motor, executive, attention) were evaluated in 9 PKU patients (6-18 years) on BH4 therapy (>5 years).
  • Behavioral assessments included ADHD Rating Scale and Behavior Rating Inventory of Executive Function (BRIEF).
  • Outcomes were compared to a previous study of PKU patients on dietary treatment.

Main Results:

  • All patients exhibited normal intelligence quotient (IQ) scores (mean=107).
  • Fine motor function was the most affected cognitive domain.
  • No significant difference in motor function was found between BH4-treated and diet-treated PKU patients.

Conclusions:

  • Long-term BH4 treatment in PKU patients maintains normal IQ but may not fully resolve fine motor impairments.
  • Current findings suggest BH4 treatment may not offer a significant advantage over dietary management for motor function.
  • Further research with larger cohorts and sensitive motor function tests is recommended to validate these findings.

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