title: Familial myopathy with conspicuous depletion of mitochondria in muscle fibers: a morphologically distinct disease.
abstract: Three patients (two of them siblings) presented with easy fatiguability and prominent postexercise pain. Muscle biopsy showed that large areas of about one third of the type II fibers were completely devoid of mitochondria. The remaining mitochondria were unusually large in size, but otherwise normal ultrastructurally. In two patients, 31P in vivo MRS showed low phosphocreatine (PCr), high ADP, low phosphorylation potential at rest and slow ADP and PCr recovery after aerobic exercise. This appears to be a pathologically unique form of metabolic myopathy. The cause of the focal mitochondrial depletion is not known. It should be distinguished from the mtDNA depletion syndrome in which muscle mitochondria are not reduced, but proliferate.
authors.affiliation: Neuromuscular Research Group, Montreal Neurological Institute, Quebec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Genge
authors.forename: G
authors.initials: G
authors.lastname: Karpati
authors.forename: D
authors.initials: D
authors.lastname: Arnold
authors.forename: E A
authors.initials: EA
authors.lastname: Shoubridge
authors.forename: S
authors.initials: S
authors.lastname: Carpenter
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D001706:Biopsy; D004272:DNA, Mitochondrial / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology*; D017240:Mitochondrial Myopathies / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000648:ultrastructure*; D018482:Muscle, Skeletal / Q000166:cytology; D010725:Phosphocreatine / Q000172:deficiency; D010766:Phosphorylation
chemical_list: D004272:DNA, Mitochondrial; D010725:Phosphocreatine; D000244:Adenosine Diphosphate