Coenzyme Q10 (Muscle)

Coenzyme Q10 (Muscle) is used for diagnosis of Coenzyme Q10 (CoQ10) deficiency that is inherited or acquired. Coenzyme Q10 Muscle may also be used for assessment of Variants of Uncertain Significance (VUS) identified during genetic testing (e.g., next-generation sequencing or capillary-sequencing testing).

Coenzyme Q10 (CoQ10) is an essential cofactor in the mitochondrial respiratory chain responsible for oxidative phosphorylation, where it functions as an electron carrier and acts as an antioxidant. It is found in all cell membranes and is carried by lipoproteins in the circulation. Approximately 60% of CoQ10 is associated with low-density lipoprotein (LDL), 25% with high-density lipoprotein (HDL) and 15% with other lipoproteins. CoQ10 is present in the body in both the reduced and oxidized forms, with the antioxidant activity of CoQ10 dependent not only on its concentration but also on its reduction-oxidation (redox) status. Primary CoQ10 deficiency, although rare, is characterized by neurological symptoms (seizures, developmental delay, ataxia, etc.) and muscle weakness. CoQ10 has been implicated in other disease processes, including Parkinson's disease, diabetes and Alzheimer's disease, as well as in aging and oxidative stress. CoQ10 may also play a role in hydroxymethylglutaryl-CoA reductase inhibitor (statin) therapy; changes in CoQ10 may be relevant to statin-induced myalgia. At least five different phenotypes of primary CoQ10 deficiency have been described: encephalomyopathy (elevated serum creatine kinase [CK], recurrent myoglobinuria, lactic acidosis), childhood-onset cerebellar ataxia and atrophy (neuropathy, hypogonadism), multisystemic infant form (nystagmus, optic atrophy, sensorineural hearing loss, dystonia, rapidly progressing nephropathy) and glomerulopathy myopathy (exercise intolerance, fatigue, elevated serum CK). Treatment with CoQ10 in patients with mitochondrial cytopathies can improve mitochondrial respiration in both brain and skeletal muscle.