title: Benign reversible muscle cytochrome c oxidase deficiency: a second case.
abstract: A 6-week-old boy had generalized weakness, requiring assisted ventilation, and lactic acidosis. At 6 months, the lactic acidosis resolved, and the patient started to improve; assisted ventilation was discontinued at 15 months. Muscle biopsies at 4 and 11 months showed accumulation of mitochondria, lipid, and glycogen; cytochrome c oxidase (COX) activity was 11% of the lowest control in the first biopsy and 57% in the second. Immunocytochemistry and immunotitration showed presence of immunologically reactive enzyme protein in both biopsies. This case confirms a previous report of benign infantile myopathy due to reversible COX deficiency. The severe fibrosis in the second biopsy may explain the slower rate of clinical recovery in this child.
mesh_terms: D001706:Biopsy; D030401:Cytochrome-c Oxidase Deficiency; D006651:Histocytochemistry; D006801:Humans; D007124:Immunoenzyme Techniques; D007223:Infant; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology* / Q000473:pathology; D009132:Muscles / Q000473:pathology*; D009135:Muscular Diseases / Q000201:enzymology* / Q000473:pathology