Muscle adenylate deaminase deficiency. Report of six new cases.

We describe six adult patients (five men and one woman) out of 364 whose muscle biopsy specimens disclosed muscle adenylate deaminase deficiency. Two men had an associated dermatomyositis and another man had an associated progressive systemic sclerosis. Although the patients were different clinically, all complained of muscular weakness or poor exercise tolerance. The occurrence of muscle adenylate deaminase deficiency in both sexes suggests a possible autosomal mode of inheritance.