COQ8B nephropathy: Early detection and optimal treatment

Background Mutations inCOQ8B(*615567) as a defect of coenzyme Q10 (CoQ10) cause steroid resistant nephrotic syndrome (SRNS). Methods To define the clinical course and prognosis of COQ8B nephropathy, we retrospectively assessed the genotype and phenotype in patients withCOQ8Bmutations from Chinese Children Genetic Kidney Disease Database. We performed the comparing study of renal outcome following CoQ10 treatment and renal transplantation between early genetic detection and delayed genetic detection group. Results We identified 20 (5.8%) patients with biallelic mutations ofCOQ8Bscreening for patients with SRNS, non-nephrotic proteinuria, or chronic kidney disease (CKD) of unknown origin. Patients withCOQ8Bmutations showed a largely renal-limited phenotype presenting with proteinuria and/or advanced CKD at the time of diagnosis. Renal biopsy uniformly showed focal segmental glomerulosclerosis. Proteinuria was decreased, whereas the renal function was preserved in five patients following CoQ10 administration combined with angiotensin-converting enzyme (ACE) inhibitor. The renal survival analysis disclosed a significantly better outcome in early genetic detection group than in delayed genetic detection group (Kaplan-Meier plot and log rank test,p = .037). Seven patients underwent deceased donor renal transplantation without recurrence of proteinuria or graft failure. Blood pressure showed decreased significantly during 6 to 12 months post transplantation. Conclusions COQ8Bmutations are one of the most common causes of adolescent-onset proteinuria and/or CKD of unknown etiology in the Chinese children. Early detection of COQ8B nephropathy following CoQ10 supplementation combined with ACE inhibitor could slow the progression of renal dysfunction. Renal transplantation in patients withCOQ8Bnephropathy showed no recurrence of proteinuria.