Coenzyme Q and mitochondrial disease

Coenzyme Q₁₀ (CoQ₁₀) is an essential electron carrier in the mitochondrial respiratory chain and an important antioxidant. Deficiency of CoQ₁₀ is a clinically and molecularly heterogeneous syndrome, which, to date, has been found to be autosomal recessive in inheritance and generally responsive to CoQ₁₀ supplementation. CoQ₁₀ deficiency has been associated with five major clinical phenotypes: (1) encephalomyopathy, (2) severe infantile multisystemic disease, (3) cerebellar ataxia, (4) isolated myopathy, and (5) nephrotic syndrome. In a few patients, pathogenic mutations have been identified in genes involved in the biosynthesis of CoQ₁₀ (primary CoQ₁₀ deficiencies) or in genes not directly related to CoQ₁₀ biosynthesis (secondary CoQ₁₀ deficiencies). Respiratory chain defects, ROS production, and apoptosis contribute to the pathogenesis of primary CoQ₁₀ deficiencies. In vitro and in vivo studies are necessary to further understand the pathogenesis of the disease and to develop more effective therapies. © 2010 Wiley-Liss, Inc. Dev Disabil Res Rev 2010;16:183–188.