Gene Defects in the Coenzyme Q10 Biosynthesis Pathway: A Previously Unrecognised Cause of Retinitis Pigmentosa

Coenzyme Q10 (CoQ10) is synthesised in the inner mitochondrial membrane across all systems with higher expression in high energy demand tissues (e.g. liver, heart, kidney, muscle, eye). CoQ10 is an essential electron carrier along the mitochondrial respiratory chain during the ATP synthesis. Thus, biallelic pathogenic variants in nuclear CoQ10 biosynthesis genes lead to a primary CoQ10 deficiency and consequent dysfunction of the respiratory chain. Clinical phenotyping has suggested retinopathy may be part of the syndromic phenotype in a number of cases of primary CoQ10 deficiency. A recent study reported a novel presentation of the disease that included nephropathy and retinopathy without neurological involvement. We investigated CoQ10 biosynthesis defects in inherited retinal dystrophy (IRD).