CYP8B1
Chr 3cytochrome P450 family 8 subfamily B member 1
Also known as: CP8B, CYP12, CYPVIIIB1
The protein is a cytochrome P450 monooxygenase that catalyzes 12alpha-hydroxylation of bile acid intermediates, controlling the balance between cholic acid and chenodeoxycholic acid production and regulating intestinal lipid absorption. Mutations cause congenital bile acid synthesis defect type 3, which presents with cholestasis, fat-soluble vitamin deficiencies, and failure to thrive, typically in infancy or early childhood. This condition follows autosomal recessive inheritance, and the gene shows low constraint to loss-of-function variation (pLI 0.00, LOEUF 1.19).
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
The highest-scoring mechanism for this gene is dominant-negative.
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
73 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 0 | 6 | 0 | 6 |
Likely Pathogenic | 0 | 0 | 1 | 0 | 1 |
VUS | 0 | 52 | 1 | 0 | 53 |
Likely Benign | 0 | 5 | 0 | 2 | 7 |
Benign | 0 | 3 | 0 | 3 | 6 |
| Total | 0 | 60 | 8 | 5 | 73 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
CYP8B1 · 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