The biochemical findings and phenotypes were consistent with Coenzyme Q10 deficiency [OMIM: 607426] with a recessive inheritance pattern, but only one variant (c.170_171insTGGGCTCGCGAGCCGC (p.F59Lfs*39)) which was predicted as a null allele was found in COQ2 gene. This evidence concerns the gene COQ2 and coenzyme Q10 deficiency.