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GTR Home > Conditions/Phenotypes > Pterin-4 alpha-carbinolamine dehydratase 1 deficiency


Tetrahydrobiopterin (BH4)-deficient hyperphenylalaninemia (HPA) D is an autosomal recessive disorder characterized by mild transient hyperphenylalaninemia often detected by newborn screening. Patients also show increased excretion of 7-biopterin. Affected individuals are asymptomatic and show normal psychomotor development, although transient neurologic deficits in infancy have been reported (Thony et al., 1998). Patients may also develop hypomagnesemia and nonautoimmune diabetes mellitus during puberty (summary by Ferre et al., 2014). For a general phenotypic description and a discussion of genetic heterogeneity of BH4-deficient hyperphenylalaninemia, see HPABH4A (261640). [from OMIM]

Available tests

35 tests are in the database for this condition.

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Genes See tests for all associated and related genes

  • Also known as: DCOH, PCBD, PCD, PHS, PCBD1
    Summary: pterin-4 alpha-carbinolamine dehydratase 1

Clinical features


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Practice guidelines

  • ACMG ACT, 2022
    American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated Phenylalanine, Phenylalanine hydroxylase deficiency (PAH), 2022
  • ACMG Algorithm, 2022
    American College of Medical Genetics and Genomics, Algorithm, PAH deficiency: Elevated Phenylalanine, 2022

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