Creatine Phosphokinase Isozymes in Neuromuscular Disorders

Serum creatine phosphokinase isozymes in 101 cases of neuromuscular disorders and 9 cases of myocardial infarction were studied by agar gel electrophoresis. Both the MM and MB types were found in some cases of unclassified muscular dystrophy and limb-girdle dystrophy, one third of dermatomyositis patients, and most of Duchenne type dystrophy and congenital muscular dystrophy patients, we well as in myocardial infarction. Because the appearances of the MB type in serum seem to indicate heart muscle involvement, these results suggest heart muscle involvement in certain muscular dystrophy, particularly the Duchenne and congenital forms.