has material basis in germline mutation in disease has basis in disruption of disease caused by disruption of QDPR 6,7-dihydropteridine reductase activity disease dihydropteridine reductase deficiency https://rarediseases.info.nih.gov/diseases/4319/dihydropteridine-reductase-deficiency https://www.malacards.org/card/hyperphenylalaninemia_bh4_deficient_c icd11.foundation:1931239861 phenylketonuria type 2 SCTID:58256000 HPABH4C GARD:0004319 dihydropteridine reductase deficiency hyperphenylalaninemia, BH4-deficient C MEDGEN:75682 6,7-dihydropteridine reductase activity disease OMIM:261630 Dihydropteridine reductase (DHPR) deficiency is a severe form of hyperphenylalaninemia (HPA) due to impaired regeneration of tetrahydrobiopterin (BH4), 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. UMLS:C0268465 MONDO:0009862 PKU type 2 hyperphenylalaninemia, BH-4-deficient, C Orphanet:226 disorder of 6,7-dihydropteridine reductase activity DOID:0081130 hyperphenylalaninemia, Bh4-deficient, type C NCIT:C138173 hyperphenylalaninemia, BH4-deficient, C hyperphenylalaninemia due to dihydropteridine reductase deficiency hyperphenylalaninemia due to tetrahydrobiopterin deficiency tetrahydrobiopterin metabolic process disease