Lactate dehydrogenase isoenzyme in detecting carriers of Duchenne muscular dystrophy.

Thirty mothers of patients with Duchenne muscular dystrophy were studied with serum enzyme tests, including serum glutamic-oxaloacetic transminase, creatine kinase, and lactate dehydrogenase isoenzymes. In addition, females from the mothers' pedigrees were studied. Lactate dehydrogenase isoenzyme 5 determinations were as senitive an indicator of carrier status as creatine kinase and also identified several mothers who had normal dehydrogenase isoenzyme 5 determinations, as well as extensive pedigree testing, identified 28 to 30 mothers as probable heterozygotes. These data independently support the suggestion that cases of Duchenne muscular dystrophy as a result of spontaneous mutation are more uncommon than currently accepted.