CYB5RL
Chr 1cytochrome b5 reductase like
The protein functions as a NADH-cytochrome b5 reductase involved in fatty acid desaturation and elongation, cholesterol biosynthesis, drug metabolism, and methemoglobin reduction in red blood cells. Mutations cause autosomal recessive congenital methemoglobinemia, which presents with cyanosis due to impaired ability to reduce methemoglobin to normal hemoglobin. This gene is highly constrained against loss-of-function variants, indicating that complete loss of protein function is likely incompatible with normal development.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Tolerant to missense variation
This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.
Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
CYB5RL · 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 →No open access results found
External Resources
Links to major genomics databases and tools