Chromosomal location of two human genes encoding tetrahydrobiopterin-metabolizing enzymes: 6-pyruvoyl-tetrahydropterin synthase maps to 11q22.3-q23.3, and pterin-4 alpha-carbinolamine dehydratase maps to 10q22.

Tetrahydrobiopterin (BH4) is the redox cofactor for the aromatic amino acid hydroxylases such as phenylalanine hydroxylase. At least five enzymes are known to be involved in BH4 biosynthesis and regeneration. A deficiency in several of the BH4 metabolic enzymes causes variant types of hyperphenylalaninemias in man. Recently, we cloned and expressed the human cDNAs for two of the BH4 enzymes, the 6-pyruvoyl-tetrahydropterin synthase and the pterin-4 alpha-carbinolamine dehydratase (gene symbols PTS and PCD/DCOH, respectively). In this report, we localized the two genes on the human chromosomes by in situ hybridization. The PTS gene was mapped to the chromosomal region 11q22.3-q23.3, and the PCD/DCOH gene was mapped to the 10q22 band of the genome.