HYPERPHENYLALANINEMIA DUE TO TETRAHYDROBIOPTERIN DEFICIENCY - A REPORT OF 16 CASES

COSKUN T., OZALP I., TOKATLI A., BLAU N., NIEDERWIESER A.

JOURNAL OF INHERITED METABOLIC DISEASE, cilt.16, sa.3, ss.605-607, 1993 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 16 Sayı: 3
  • Basım Tarihi: 1993
  • Doi Numarası: 10.1007/bf00711694
  • Dergi Adı: JOURNAL OF INHERITED METABOLIC DISEASE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.605-607
  • Hacettepe Üniversitesi Adresli: Evet

Özet

Tetrahydrobiopterin (BH4) deficiency accounts for 1-3% of all reported forms of hyperphenylalaninaemia (HPA). Deficiencies of two enzymes, GTP-cyclohydrolase (GTPch; EC 3.5.4.16) and 6-pyruvoyl tetrahydropterin synthase (6-PTS), lead to a defect in BH4 biosynthesis. During the hydroxylation of phenylalanine (Phe) to tyrosine by phenylalanine hydroxylase (PAH; EC 1.14.16.1), BH, is oxidized to quinonoid dihydrobiopterin (qBH2). In order to regenerate BH4, qBH2 is reduced by the enzyme dihydropteridin reductase (DHPR; EC 1.6.99.7). More recently a new form (primapterinuria) due to a possible defect in the activity of dehydratase has been described. Since BH4 is required as cofactor by PAH and by mammalian aromatic amino acid hydroxylases, a deficiency leads not only to HPA but also to a deficiency of biogenic amine neurotransmitters dopamine and serotonin (Blau 1988), its clinical picture and mode of therapy would be expected to be different from the other types of HPA.