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Dihydropteridine reductase deficiency

Disease definition

Dihydropteridine reductase (DHPR) deficiency is a severe form of hyperphenylalaninemia (HPA) due to impaired regeneration of tetrahydrobiopterin (BH4) (see this term), leading to decreased levels of neurotransmitters (dopamine, serotonin) and folate in cerebrospinal fluid, and causing neurological symptoms such as psychomotor delay, hypotonia, seizures, abnormal movements, hypersalivation, and swallowing difficulties.


Classification level: Subtype of disorder
  • Synonym(s):
    • Hyperphenylalaninemia due to dihydropteridine reductase deficiency
    • PKU type 2
    • Phenylketonuria type 2
  • Prevalence: Unknown
  • Inheritance: Autosomal recessive 
  • Age of onset: Infancy, Neonatal
  • ICD-10: E70.1
  • OMIM: 261630
  • UMLS: C0268465  C2936906
  • MeSH: C537896
  • GARD: 4319
  • MedDRA: -

Detailed information


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