title: Mitochondrial encephalomyopathy with coenzyme Q10 deficiency.
abstract: Coenzyme Q10 (CoQ10) transfers electrons from complexes I and II of the mitochondrial respiratory chain to complex III. There is one published report of human CoQ10 deficiency describing two sisters with encephalopathy, proximal weakness, myoglobinuria, and lactic acidosis. We report a patient who had delayed motor milestones, proximal weakness, premature exertional fatigue, and episodes of exercise-induced pigmenturia. She also developed partial-complex seizures. Serum creatine kinase was approximately four times the upper limit of normal and venous lactate was mildly elevated. Skeletal muscle biopsy revealed many ragged-red fibers, cytochrome c oxidase-deficient fibers, and excess lipid. In isolated muscle mitochondria, impaired oxygen consumption was corrected by the addition of decylubiquinone. During standardized exercise, ventilatory and circulatory responses were compatible with a defect of oxidation-phosphorylation, which was confirmed by near-infrared spectroscopy analysis. Biochemical analysis of muscle extracts revealed decreased activities of complexes I+II and I+III, while CoQ10 concentration was less than 25% of normal. With a brief course of CoQ10 (150 mg daily), the patient reported subjective improvement. The triad of CNS involvement, recurrent myoglobinuria, and ragged-red fibers should alert clinicians to the possibility of CoQ10 deficiency.
authors.affiliation: H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Diseases, Department of Neurology, Columbia-Presbyterian Medical Center, New York, NY 10032, USA.
authors.forename: C
authors.initials: C
authors.lastname: Sobreira
authors.forename: M
authors.initials: M
authors.lastname: Hirano
authors.forename: S
authors.initials: S
authors.lastname: Shanske
authors.forename: R K
authors.initials: RK
authors.lastname: Keller
authors.forename: R G
authors.initials: RG
authors.lastname: Haller
authors.forename: E
authors.initials: E
authors.lastname: Davidson
authors.forename: F M
authors.initials: FM
authors.lastname: Santorelli
authors.forename: A F
authors.initials: AF
authors.lastname: Miranda
authors.forename: E
authors.initials: E
authors.lastname: Bonilla
authors.forename: D S
authors.initials: DS
authors.lastname: Mojon
authors.forename: A A
authors.initials: AA
authors.lastname: Barreira
authors.forename: M P
authors.initials: MP
authors.lastname: King
authors.forename: S
authors.initials: S
authors.lastname: DiMauro
mesh_terms: D000328:Adult; D003067:Coenzymes; D005260:Female; D006801:Humans; D008931:Mitochondria, Muscle / Q000378:metabolism; D017237:Mitochondrial Encephalomyopathies / Q000378:metabolism* / Q000503:physiopathology; D009994:Osmolar Concentration; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D010809:Physical Fitness; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D003067:Coenzymes; D014451:Ubiquinone; C024989:coenzyme Q10