CYB5R3
Chr 22ARcytochrome b5 reductase 3
Also known as: B5R, DIA1
Cytochrome b5 reductase catalyzes the reduction of cytochrome b5 using NADH, with the membrane-bound form functioning in fatty acid metabolism and cholesterol biosynthesis, and the soluble erythrocyte form reducing methemoglobin. Mutations cause autosomal recessive methemoglobinemia, which can be limited to erythrocytes (type I) or involve multiple organ systems with neurological manifestations (type II). The gene shows low constraint against loss-of-function variants.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Tolerant to missense variation
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
CYB5R3 · 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