title: Histiocytoid cardiomyopathy of infancy: deficiency of reducible cytochrome b in heart mitochondria.
abstract: A 3-week-old girl with failure to thrive and cardiomegaly died of cardiac arrest at age 4 weeks. Morphologic studies of the heart showed enlarged muscle fibers with large accumulations of mitochondria, characteristic of histiocytoid cardiomyopathy. Biochemical studies showed markedly decreased succinate-cytochrome c reductase and rotenone-sensitive NADH-cytochrome c reductase activities, while other mitochondrial enzymes were normal. In isolated mitochondria, cytochrome spectra showed a severe defect of reducible cytochrome b and a less marked defect of cytochrome cc1, while the content of cytochrome aa3 (cytochrome c oxidase) was normal. Histiocytoid cardiomyopathy appears to be due to a defect of complex III (reduced coenzyme Q-cytochrome c reductase) in the respiratory chain of heart mitochondria.
mesh_terms: D009202:Cardiomyopathies / Q000151:congenital* / Q000201:enzymology / Q000473:pathology; D003573:Cytochrome b Group / Q000172:deficiency*; D030401:Cytochrome-c Oxidase Deficiency; D004562:Electrocardiography; D005260:Female; D006644:Histiocytes / Q000648:ultrastructure; D006801:Humans; D007231:Infant, Newborn; D008929:Mitochondria, Heart / Q000201:enzymology* / Q000648:ultrastructure; D009206:Myocardium / Q000473:pathology; D009245:NADH Dehydrogenase / Q000172:deficiency; D010084:Oxidation-Reduction; D013384:Succinate Cytochrome c Oxidoreductase / Q000172:deficiency
chemical_list: D003573:Cytochrome b Group; D013384:Succinate Cytochrome c Oxidoreductase; D009245:NADH Dehydrogenase