COX4I1

Chr 16AR

cytochrome c oxidase subunit 4I1

Also known as: COX IV-1, COX4, COX4-1, COXIV, COXIV-1, MC4DN16

NCBI Gene: 1327 ENSG00000131143 UniProt: P13073

Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane. The complex consists of 13 mitochondrial- and nuclear-encoded subunits. The mitochondrially-encoded subunits perform the electron transfer and proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex. This gene encodes the nuclear-encoded subunit IV isoform 1 of the human mitochondrial respiratory chain enzyme. It is located at the 3' of the NOC4 (neighbor of COX4) gene in a head-to-head orientation, and shares a promoter with it. Pseudogenes related to this gene are located on chromosomes 13 and 14. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jan 2016]

Primary Disease Associations & Inheritance

Mitochondrial complex IV deficiency, nuclear type 16MIM #619060

ClinVar variants

Pathogenic / LP

0.39

pLI score

Active trials

Clinical Summary— COX4I1

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Gene-Disease Validity (ClinGen)

Leigh syndrome · ARLimited

Limited evidence — not for standalone diagnostic reporting

2 total gene-disease associations curated

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Population Constraint (gnomAD)

Constrained for loss-of-function variants (OE-LoF 0.22) despite low pLI — interpret in context.

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ClinVar Variants

46 Pathogenic / Likely Pathogenic· 40 VUS of 95 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.

0.68LOEUF

pLI 0.394

Z-score 2.21

OE 0.22 (0.09–0.68)

Tolerant

Typical tolerance to LoF variation

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.

-0.17Z-score

OE missense 1.05 (0.90–1.23)

112 obs / 106.9 exp

Tolerant

Tolerant to missense variation

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.0.22 (0.09–0.68)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.1.05 (0.90–1.23)

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.1.11

0≤1.21.6

LoF obs/exp: 2 / 9.3Missense obs/exp: 112 / 106.9Syn Z: -0.54