COQ5 and diabetic kidney disease: The reduced activation of OXPHOS appears to play a role in DKD, as suggested by findings showing associations between certain genetic mutations in OXPHOS, such as single-nucleotide polymorphisms (SNPs) in coenzyme Q5 (COQ5) and cytochrome c oxidase subunit 6A1 (COX6A1), and DKD in humans (Swan et al., 2015).