BCS1L
Chr 2ARBCS1 ubiquinol-cytochrome c reductase complex chaperone
Also known as: BCS, BCS1, BJS, FLNMS, GRACILE, Hs.6719, MC3DN1, PTD
The protein is essential for assembly of mitochondrial respiratory chain complex III. Autosomal recessive mutations cause mitochondrial complex III deficiency, GRACILE syndrome (growth restriction, aminoaciduria, cholestasis, iron overload, lactic acidosis, and early death), and Bjornstad syndrome. The pathogenic mechanism involves loss of function leading to defective complex III assembly and impaired cellular respiration.
Limited evidence — not for standalone diagnostic reporting
3 total gene-disease associations curated
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
400 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 | 13 | 3 | 10 | 0 | 26 |
Likely Pathogenic | 46 | 13 | 0 | 2 | 61 |
VUS | 1 | 102 | 8 | 5 | 116 |
Likely Benign | 0 | 3 | 62 | 111 | 176 |
Benign | 1 | 0 | 4 | 0 | 5 |
Conflicting | — | 7 | |||
| Total | 61 | 121 | 84 | 118 | 391 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
BCS1L · 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