Abstract
PDSS1 mutations hamper Coenzyme Q10 biosynthesis and cause a rare multisystem mitochondrial disease characterized by diverse clinical features and limited treatment options. To date, renal involvement has been reported in only one patient. We report a new female patient with compound heterozygous PDSS1 mutations and the clinical outcome following a trial of Coenzyme Q10 therapy. Our patient presented with developmental delay and regression at age three, which progressed to steroid-resistant nephrotic syndrome at age six, leading to stage 5 chronic kidney disease. Whole exome sequencing identified two pathogenic variants in the PDSS1 gene. High doses of Coenzyme Q10 therapy had no effect at this advanced stage of disease. Coenzyme Q10 treatment did not appear to improve the clinical outcome in this patient. Further data is needed to better understand the phenotypic spectrum of PDSS1-associated disruption, and the potential benefit of early Coenzyme Q10 therapy.