Serum Enzyme Studies in Muscular Dystrophy. III. Serum Malic Dehydrogenase, 5-Nucleotidase and Adenosinetriphosphatase.

Abstract

In-creases in serum enzyme levels in muscular dystrophy suggest the possibility that a pattern characteristic of the disease may be uncovered. In the present study data are reported for 73 patients of both sexes ranging from 2 to 73 years in age and including 43 of the acute (childhood or pseudohypertrophic) and 30 of the chronic (adult slowly progressive or myotonic) varieties. 5-Nucleotidase and ATP-ase were not found to be elevated in subjects with either acute or chronic muscular dystrophy. Patients with severe generalized rapidly progressive (acute) dystrophy had high serum levels of malic dehydrogenase as well as GOT, GPT, LDH, and aldolase. The patients with mild restricted slowly progressive (chronic) dystrophy had normal serum levels of most of these enzymes except that aldolase was slightly elevated in a few cases. It is suggested that an increase in muscle membrane permeability, probably a secondary lesion, allows a continuous leakage of these enzymes. An additional defect may exist in the mitochondrial membrane to permit the escape of malic dehydrogenase.