title: Recurrent myoglobinuria and deranged acylcarnitines due to a mutation in the mtDNA MT-CO2 gene.
abstract: Mitochondrial myopathies commonly present with exercise intolerance typified by breathlessness and fatigue on exercise. In contrast, exercise-induced rhabdomyolysis and myoglobinuria occur rarely. We present a 43-year-old man with a lifelong history of exercise intolerance associated with myalgia and recurrent episodes of exercise-induced myoglobinuria. From early childhood, he had weekly episodes of myoglobinuria, which became infrequent (every 3 months) as an adult. Carnitine transporter defect was suspected, because carnitine levels were low in muscle. During childhood, he was treated with carnitine (4-5 g daily), but without effect. With the advent of acylcarnitines, profiles mimicking but not diagnostic for multiple acyl-CoA dehydrogenase deficiency (MADD) were found. This led to treatment with riboflavin (100 mg/day for 3 years), again without effect. Clinical examination, including echocardiography, revealed no signs of involvement from other organs, and all relatives were asymptomatic.
authors.affiliation: Rigshospitalet, University of Copenhagen, Denmark. vissing@rh.dk
authors.forename: Christoffer Rasmus
authors.initials: CR
authors.lastname: Vissing
authors.forename: Morten
authors.initials: M
authors.lastname: Duno
authors.forename: Jess Have
authors.initials: JH
authors.lastname: Olesen
authors.forename: Jabin
authors.initials: J
authors.lastname: Rafiq
authors.forename: Lotte
authors.initials: L
authors.lastname: Risom
authors.forename: Ernst
authors.initials: E
authors.lastname: Christensen
authors.forename: Flemming
authors.initials: F
authors.lastname: Wibrand
authors.forename: John
authors.initials: J
authors.lastname: Vissing
mesh_terms: D000328:Adult; D002331:Carnitine / Q000031:analogs & derivatives* / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D009212:Myoglobinuria / Q000175:diagnosis* / Q000235:genetics*; D012008:Recurrence
chemical_list: D004272:DNA, Mitochondrial; C116917:acylcarnitine; C117108:cytochrome C oxidase subunit II; D003576:Electron Transport Complex IV; D002331:Carnitine