QDPR

Chr 4AR

quinoid dihydropteridine reductase

Also known as: DHPR, HDHPR, PKU2, SDR33C1

NCBI Gene: 5860 ENSG00000151552 UniProt: P09417 OMIM: 612676

Dihydropteridine reductase catalyzes the NADH-mediated reduction of quinonoid dihydrobiopterin and is an essential component of pterin-dependent aromatic amino acid hydroxylating systems. Autosomal recessive mutations cause BH4-deficient hyperphenylalaninemia, which presents as atypical phenylketonuria due to insufficient biopterin production, a required cofactor for phenylalanine hydroxylase. Pathogenic variants include splicing defects, amino acid substitutions, insertions, and premature terminations that result in enzyme deficiency.

OMIM ResearchSummary from RefSeq, OMIM, Mechanism

This gene encodes the enzyme dihydropteridine reductase, which catalyzes the NADH-mediated reduction of quinonoid dihydrobiopterin. This enzyme is an essential component of the pterin-dependent aromatic amino acid hydroxylating systems. Mutations in this gene resulting in QDPR deficiency include aberrant splicing, amino acid substitutions, insertions, or premature terminations. Dihydropteridine reductase deficiency presents as atypical phenylketonuria due to insufficient production of biopterin, a cofactor for phenylalanine hydroxylase. [provided by RefSeq, Jul 2008]

OMIM ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

Hyperphenylalaninemia, BH4-deficient, CMIM #261630

Clinical highlights

Gene-disease validity (ClinGen)

dihydropteridine reductase deficiency · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

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P/LP submissions

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P/LP missense

1.06

LOEUF

LOF

Mechanism· G2P