Atypical kinase COQ8B, mitochondrial (COQ8B)

Atypical kinase COQ8B, mitochondrial (COQ8B) is an atypical mitochondrial serine/threonine kinase that plays a regulatory role in the biosynthesis of coenzyme Q10 (ubiquinone), a key lipid in the mitochondrial electron transport chain essential for oxidative phosphorylation, ATP synthesis, and cellular antioxidant defense[1][2][4]. COQ8B is crucial for the development and function of podocytes and the glomerular basement membrane, with loss-of-function mutations leading to *autosomal recessive nephrotic syndrome type 9* (NPHS9), characterized by proteinuria, chronic kidney disease, and progression to end-stage renal disease (ESRD)[2][3]. Mutations may result in systemic primary coenzyme Q10 deficiency, affecting brain, muscle, and other tissues[1][2]. The protein is classified as an *atypical ABC1-family kinase*, is localized to the mitochondrial matrix, and is inherited in an autosomal recessive manner when mutated[1][2][3]. For patients with COQ8B deficiency, *exogenous coenzyme Q10 supplementation* may partially restore mitochondrial function and delay progression of kidney disease, but early diagnosis is critical since standard immunosuppressive therapies for nephrotic syndrome are typically ineffective in these cases[2].

Other names

aarF domain-containing kinase 4ADCK4coenzyme Q protein 8BFLJ12229NPHS9COQ8aarF domain-containing protein kinase 4

Restoration of CoQ10 levels by exogenous supplementation (for pathogenic loss-of-function variants)