COA6 is involved in the maturation of the mitochondrial respiratory chain complex IV subunit MT-CO2/COX2 []. Mutations in the COA6 gene cause cardioencephalomyopathy due to cytochrome c oxidase deficiency 4 (CEMCOX4), and an infantile disorder with a fatal course in the first weeks of life, characterised by hypertrophic cardiomyopathy, left ventricular non-compaction, lactic acidosis, metabolic hypotonia, and mitochondrial complex IV deficiency [].
