Coenzyme Q10(Co Q10) is an essential cofactor in the mitochondrial respiratory pathway and also functions as a lipid-soluble antioxidant. Co Q10 deficiency has been implicated in many clinical disorders and aging. Primary Co Q10 deficiency is a group of recessively inherited diseases caused by mutations in any gene involved in the Co Q10 biosynthesis pathway. Although primary Co Q10 deficiency is rare, its diagnosis is important because it is potentially treatable with exogenous Co Q10. Multiple system atrophy(MSA) was recently shown to be linked to mutations in the COQ2 gene, one of the genes involved in the Co Q10 biosynthesis pathway. MSA is relatively common in adult-onset neurodegenerative diseases characterized by Parkinsonism, cerebellar ataxia and autonomic failures. Because COQ2 mutations are associated with an increased risk of MSA, oral Co Q10 supplementation may be beneficial for MSA, as for other primary Co Q10 deficiencies. Statins are 3-hydroxy-3-methylglutaryl coenzyme A inhibitors that inhibit the biosynthesis of cholesterol, as well as the synthesis of mevalonate, a critical intermediate in cholesterol synthesis. Statin therapy has been associ-ated with a variety of muscle complaints from myalgia to rhabdomyolysis. Statin treatment carries a potential risk of Co Q10 deficiency, although no definite evidence has implicated CQ10 deficiency as the cause of statinrelated myopathy. Co Q10 deficiency has been implicated in many clinical disorders and aging. CoQ10 deficiency is a essential cofactor in the mitochondrial respiratory pathway and also functions as a lipid-soluble antioxidant. Co Q10 deficiency has been implicated in many clinical disorders and aging. by mutations in any gene involved in the Co Q10 biosynthesis pathway. Although primary Co Q10 deficiency is rare, its diagnosis is important because it is potentially treatable with exogenous Co Q10. Multiple system atrophy (MSA) was recently shown to be linked to mutations in the COQ2 gene, one of the genes involved in the Co Q10 biosynthesis pathway. MSA is relatively common in adult-onset neurodegenerative diseases characterized by Parkinsonism, cerebellar ataxia and autonomic failures. Because COQ2 mutations are associated with an increased risk of MSA, oral Co Q10 supplementation may be beneficial for MSA, as for other primary Co Q10 deficiencies. Statins are 3-hydroxy-3-methylglutaryl coenzyme A inhibitors that inhibit the biosynthesis of cholesterol, as well as the synthesis of mevalonate, a critical intermediate in cholesterol synthesis. Statin therapy has been associ-ated with a variety of muscle complaints from myalgia to rhabdomyolysis. Statin treatment carrying a potential risk of Co Q10 deficiency, although no definite evidence has implicated CQ10 deficiency as the cause of statinrelated myopathy.