Features include always present findings: Thickened heart muscle (hypertrophic cardiomyopathy), Cardiomyocyte mitochondrial proliferation, and Decreased activity of mitochondrial complex IV.

COA5 encodes cytochrome c oxidase assembly factor 5 (74 aa). Assembly factor for cytochrome c oxidase (respiratory chain complex IV). Highest expression in Brain Cerebellar Hemisphere (62.5 TPM) and Brain Cerebellum (56.2 TPM).

Cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency 3 is associated with mutations in the COA5 gene on chromosome 2.

The COA5 protein participates in Metallochaperone inserts 2Cu2+ into MT-CO2 and Metallochaperone inserts Cu2+ into MT-CO1 pathways.

COA5 is classified as a druggable target with score 0.0.

Genetic testing for COA5 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 3 always present features.