Tetrahydrobiopterin responsiveness in phenylketonuria differs between patients with the same genotype

Mol Genet Metab. 2001 May;73(1):104-6. doi: 10.1006/mgme.2001.3168.


Recently, BH(4)-responsive phenylalanine hydroxylase (PAH) deficiency was reported in patients with specific mutations in the PAH gene, and it was suggested that BH(4) responsiveness may be determined by the respective genotypes. We now report on three patients with PAH deficiency and the same genotype but different responses to standardized BH(4) loading. Our results suggest that BH(4) responsiveness in PAH deficiency is at least partly independent from PAH genotype.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Biopterin / administration & dosage*
  • Biopterin / analogs & derivatives
  • Genotype
  • Heterozygote
  • Humans
  • Infant, Newborn
  • Mutation
  • Phenylalanine / blood
  • Phenylalanine / drug effects
  • Phenylalanine Hydroxylase / deficiency
  • Phenylalanine Hydroxylase / genetics*
  • Phenylketonurias / enzymology
  • Phenylketonurias / genetics*
  • Pterins / urine


  • Pterins
  • Biopterin
  • Phenylalanine
  • Phenylalanine Hydroxylase