Orphanet: Hyperphenylalaninemia due to tetrahydrobiopterin deficiency

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Hyperphenylalaninemia due to tetrahydrobiopterin deficiency

Disease definition

Hyperphenylalaninemia (HPA) due to tetrahydrobiopterin (BH4) deficiency, also known as malignant HPA is an amino acid disorder with neonatal onset that is clinically characterized by the classic manifestations of phenylketonuria (PKA; see this term) and that later on is clinically differentiated by neurologic symptoms such as microcephaly, intellectual disability, central hypotonia, delayed motor development, peripheral spasticity and seizures, that develop and persist despite an established metabolic control of plasma phenylalanine.


Classification level: Disorder
  • Synonym(s):
    • Hyperphenylalaninemia due to BH4 deficiency
    • Non-phenylketonuric hyperphenylalaninemia
  • Prevalence: 1-9 / 1 000 000
  • Inheritance: Autosomal recessive 
  • Age of onset: Neonatal, Infancy
  • ICD-10: E70.1
  • OMIM: 233910  261630  261640  264070
  • UMLS: C0751435  C0751436
  • MeSH: -
  • GARD: 7751
  • MedDRA: -

Detailed information


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