COX6A2

Chr 16AR

cytochrome c oxidase subunit 6A2

Also known as: COX6AH, COXVIAH, COXVIa-M, MC4DN18

The COX6A2 protein is a structural subunit of cytochrome c oxidase (complex IV) that is specifically expressed in heart and skeletal muscle, where it contributes to the assembly and stabilization of this terminal enzyme in the mitochondrial respiratory chain. Mutations cause autosomal recessive mitochondrial complex IV deficiency, presenting as a multisystem disorder affecting high-energy demanding tissues including muscle, heart, brain, and liver. Clinical manifestations typically include myopathy, cardiomyopathy, developmental delays, and metabolic acidosis with variable age of onset from infancy to childhood.

OMIMResearchSummary from RefSeq, UniProt
MultiplemechanismARLOEUF 1.581 OMIM phenotype
Clinical SummaryCOX6A2
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Gene-Disease Validity (ClinGen)
mitochondrial disease · ARModerate

Moderate evidence — consider for supplementary testing

Population Constraint (gnomAD)
Low constraint (pLI 0.19) — loss-of-function variants are relatively tolerated in the population.
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Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.58LOEUF
pLI 0.189
Z-score 0.93
OE 0.38 (0.131.58)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
0.24Z-score
OE missense 0.90 (0.701.17)
41 obs / 45.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.38 (0.131.58)
00.351.4
Missense OE0.90 (0.701.17)
00.61.4
Synonymous OE0.90
01.21.6
LoF obs/exp: 1 / 2.6Missense obs/exp: 41 / 45.5Syn Z: 0.35
DN
0.76top 25%
GOF
0.6442th %ile
LOF
0.3647th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median
GOFprediction above median

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

COX6A2 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold
Clinical Literature
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