title: Muscle involvement in pyruvate dehydrogenase complex (PDHC) deficiency.
abstract: Muscle biopsies from a 13-month-old female infant with a delay in developmental milestones, lactic acidosis and visual disturbance, and a 6 year-old female with frequent epileptic fits are described. Biochemical studies of biopsied muscles and skin fibroblasts demonstrated markedly decreased pyruvate dehydrogenase complex (PDHC) activity to about 16% of normal value. Muscle histochemistry in both patients showed disorganized intermyofibrillar networks containing large diformazan granules on NADH-TR, small angulated fibers with high nonspecific esterase (NSE) activity and basophilic fibers. Ragged-red fibers and increased lipid droplet accumulation were absent. Patient 1 had increased numbers of type 2C fibers (11.3%) and mild fiber type grouping. On electron microscopy, most mitochondria were nearly normal. There were focal aggregates of mildly enlarged mitochondria in the subsarcolemmal areas in both patients. Morphometric study showed that the mean mitochondrial size and the mitochondrial percentage of fiber volume were not significantly different amongst patients and normal controls.
mesh_terms: D002648:Child; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006651:Histocytochemistry; D006801:Humans; D007223:Infant; D008854:Microscopy, Electron; D008931:Mitochondria, Muscle / Q000648:ultrastructure; D009132:Muscles / Q000201:enzymology* / Q000648:ultrastructure; D009135:Muscular Diseases / Q000201:enzymology* / Q000473:pathology; D011768:Pyruvate Dehydrogenase Complex / Q000032:analysis; D015325:Pyruvate Dehydrogenase Complex Deficiency Disease
chemical_list: D011768:Pyruvate Dehydrogenase Complex