COX6A2

Chr 16AR

cytochrome c oxidase subunit 6A2

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

NCBI Gene: 1339 ENSG00000156885 UniProt: Q02221

Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. It is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may be involved in the regulation and assembly of the complex. This nuclear gene encodes polypeptide 2 (heart/muscle isoform) of subunit VIa, and polypeptide 2 is present only in striated muscles. Polypeptide 1 (liver isoform) of subunit VIa is encoded by a different gene, and is found in all non-muscle tissues. These two polypeptides share 66% amino acid sequence identity. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Mitochondrial complex IV deficiency, nuclear type 18MIM #619062

ClinVar variants

Pathogenic / LP

0.19

pLI score

Active trials

Clinical Summary— COX6A2

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Gene-Disease Validity (ClinGen)

mitochondrial disease · ARModerate

Moderate evidence — consider for supplementary testing

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Population Constraint (gnomAD)

Low constraint (pLI 0.19) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

10 Pathogenic / Likely Pathogenic· 28 VUS of 42 total submissions

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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

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.

1.58LOEUF

pLI 0.189

Z-score 0.93

OE 0.38 (0.13–1.58)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.

0.24Z-score

OE missense 0.90 (0.70–1.17)

41 obs / 45.5 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.

LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.38 (0.13–1.58)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.90 (0.70–1.17)

0≤0.61.4

Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.90

0≤1.21.6

LoF obs/exp: 1 / 2.6Missense obs/exp: 41 / 45.5Syn Z: 0.35