Primapterinuria: A New Variant of Atypical Phenylketonuria

  • Nenad Blau
  • H. Ch. Curtius
  • Th. Kuster
  • A. Matasovic
  • G. Schoedon
  • J. L. Dhondt
  • P. Guibaud
  • T. Giudici
  • M. Blaskovics

Abstract

Primapterin (7-iso-biopterin) is a new pterin metabolite found recently in the urine of a child with mild hyperphenylalaninaemia (Dhondt et al.,1988). Besides primapterin two other new 7-substituted pterins, namely 6-oxo-primapterin and anapterin (7-iso-neopterin), were also found in the patient’s urine, however in much lower concentrations (Curtius et al., 1988). In the meantime a second patient has been diagnosed with primapterinuria and transient hyperphenylalaninaemia (Blaskovics, personal communication). In both cases a tetrahydrobiopterin (BH4) loading test normalized plasma phenylalanine levels after 4 to 6 h. In both patients the cerebrospinal fluid (CSF) neurotransmitter metabolites, 5-hydroxyindoleacetic acid and homovanillic acid were in the normal range and the activities of all enzymes of the BH4 biosynthesis and regeneration (GTP cyclohydrolase I, 6-pyruvoyltetrahydropterin synthase, sepiapterin reductase and dihydropteridine reductase) were found to be normal. The neopterin to biopterin ratio of the patients’ urine was significantly increased. Following oral tetrahydrobiopterin administration (2 mg kg−1d−1) neopterin normalized and biopterin as well as primapterin increased about eight-fold in one of the patients. This finding suggests that primapterin is formed from biopterin by an isomerization reaction. However, the exact metabolic origin of primapterin and anapterin is still obscure.

Keywords

Homovanillic Acid Isomerization Reaction Dihydropteridine Reductase Sepiapterin Reductase Neurotransmitter Metabolite 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Curtius, H. Ch., Kuster, Th., Matasovic, A., Blau, N. and Dhondt, J. L. Primapterin, anapterin, and 6-oxo-primapterin, three new 7-substituted pterins identified in a patient with hyperphenylalaninemia. Biochem. Biophys. Res. Commun. 153 (1988) 715–721PubMedCrossRefGoogle Scholar
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Copyright information

© SSIEM and Kluwer Academic Publishers 1989

Authors and Affiliations

  • Nenad Blau
    • 1
  • H. Ch. Curtius
    • 1
  • Th. Kuster
    • 1
  • A. Matasovic
    • 1
  • G. Schoedon
    • 1
  • J. L. Dhondt
    • 2
  • P. Guibaud
    • 3
  • T. Giudici
    • 4
  • M. Blaskovics
    • 5
  1. 1.Division of Clinical Chemistry, Department of PediatricsUniversity of ZurichZurichSwitzerland
  2. 2.Laboratoire de BiochimieUniversity of LilleLille CedexFrance
  3. 3.Centre d’Etude des Maladies MetaboliquesHôpital DebrousseLyonFrance
  4. 4.Division of GeneticsChildrens HospitalLos AngelesUSA
  5. 5.Department of PediatricsKaiser PermanenteFontanaUSA

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