Novel Coenzyme Q2 (CoQ2) Mutation in a Pediatric Patient With Primary Steroid-Resistant Nephrotic Syndrome Due to Coenzyme Q10 (CoQ10) Deficiency.

Coenzyme Q2 (CoQ2) mutations are a group of autosomal recessive mitochondria-linked diseases that result in coenzyme Q10 (CoQ10) deficiency (CoQ10: a cofactor in mitochondrial energy production). Its deficiency leads to multiple systemic clinical presentations; however, isolated steroid-resistant nephrotic syndrome (SRNS) is considerably rare. Multiple genetic mutations have been reported with different ranges of severity and prognosis, with variable responses to CoQ10 supplementation. This case report describes a boy with CoQ10 deficiency due to a novel homozygous variation in the CoQ2 gene, c.1112T>A, p.(Leu371Gln). The patient presented with isolated SRNS, and oral supplementation of CoQ10 resulted in remission.