COQ8A and coenzyme Q10 deficiency: Pathogenic variants in 8 of the 13 genes involved in the CoQ10 biosynthetic pathway (PDSS1, PDSS2, COQ2, COQ4, COQ6, ADCK3 or COQ8A, COQ9) have been ascribed to primary CoQ10 deficiency, usually having an autosomal recessive pattern of inheritance.