Rescue of primary ubiquinone deficiency due to a novel COQ7 defect using 2,4–dihydroxybensoic acid

BACKGROUND Coenzyme Q is an essential mitochondrial electron carrier, redox cofactor and a potent antioxidant in the majority of cellular membranes. Coenzyme Q deficiency has been associated with a range of metabolic diseases, as well as with some drug treatments and ageing. METHODS We used whole exome sequencing (WES) to investigate patients with inherited metabolic diseases and applied a novel ultra-pressure liquid chromatography-mass spectrometry approach to measure coenzyme Q in patient samples. RESULTS We identified a homozygous missense mutation in the COQ7 gene in a patient with complex mitochondrial deficiency, resulting in severely reduced coenzyme Q levels We demonstrate that the coenzyme Q analogue 2,4-dihydroxybensoic acid (2,4DHB) was able to specifically bypass the COQ7 deficiency, increase cellular coenzyme Q levels and rescue the biochemical defect in patient fibroblasts. CONCLUSION We report the first patient with primary coenzyme Q deficiency due to a homozygous COQ7 mutation and a potentially beneficial treatment using 2,4DHB.