CYC1
Chr 8ARcytochrome c1
Also known as: MC3DN6, UQCR4
The CYC1 protein is a catalytic core subunit of mitochondrial respiratory chain complex III (cytochrome bc1 complex) that transfers electrons from the Rieske iron-sulfur protein to cytochrome c during oxidative phosphorylation. Autosomal recessive mutations cause mitochondrial complex III deficiency, nuclear type 6, a disorder affecting cellular energy production. The gene shows moderate constraint to loss-of-function variants (LOEUF 0.639), consistent with its essential role in mitochondrial respiration.
Moderate evidence — consider for supplementary testing
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
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
257 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 | 2 | 56 | 0 | 58 |
Likely Pathogenic | 0 | 0 | 5 | 0 | 5 |
VUS | 3 | 94 | 12 | 3 | 112 |
Likely Benign | 1 | 2 | 25 | 31 | 59 |
Benign | 0 | 1 | 12 | 3 | 16 |
Conflicting | — | 1 | |||
| Total | 4 | 99 | 110 | 37 | 251 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
CYC1 · 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
External Resources
Links to major genomics databases and tools