Serum cytoplasmic and mitochondrial aspartate aminotransferase in Duchenne's progressive muscular dystrophy.

The activities of cytoplasmic and mitochondrial aspartate aminotransferase isoforms in serum in 20 outpatients with Duchenne's progressive muscular dystrophy and seven carriers of the gene of that disease were determined. The control group consisted of 19 patients with other neuromuscular disorders. Twenty, age-matched healthy persons comprised the normal control group. The activity of the cytoplasmic isoform was increased in 85% of Duchenne's dystrophy cases. In these cases the reaction of the cytoplasmic isoenzyme in the presence of pyridoxal 5'-phosphate was abnormal. In the remaining Duchenne's dystrophy cases normal activity of this isoform and normal stimulation to pyridoxal 5'-phosphate was found. The mitochondrial isoform was significantly increased in 30% of Duchenne's dystrophy cases. In all Duchenne's dystrophy patients the reaction of the mitochondrial isoenzyme to supplementation with pyridoxal 5'-phosphate was normal. We conclude that the evaluation of aspartate aminotransferase isoforms in serum in Duchenne's dystrophy can be of clinical importance, especially in evaluating the degree of muscle cell damage.