COQ9Ubiquinone biosynthesis protein COQ9, mitochondrial, also known as coenzyme Q9 homolog, is a protein that in humans is encoded by the COQ9 gene.FunctionThis locus represents a mitochondrial ubiquinone biosynthesis gene. The encoded protein is likely necessary for biosynthesis of coenzyme Q10, as mutations at this locus have been associated with autosomal-recessive neonatal-onset primary coenzyme Q10 deficiency.Clinical significanceIt may be associated with Coenzyme Q10 deficiency.