QDPR
Chr 4ARquinoid dihydropteridine reductase
Also known as: DHPR, HDHPR, PKU2, SDR33C1
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.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
QDPR · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools