Primary CoQ10 deficiency-6 (COQ10D6, OMIM # 614650) is an autosomal recessive disorder that manifests as severe progressive infantile-onset NS resulting in end-stage renal failure and sensorineural hearing loss (SNHL) due to homozygous or compound heterozygous mutations in the COQ6 gene located on chromosome 14q24.3, which encodes an evolutionarily conserved flavin-dependent monooxygenase required for CoQ10 biosynthesis. Here, COQ6 is linked to familial steroid-resistant nephrotic syndrome with sensorineural deafness.