Abstract
The characteristic clinical features of 2 cases of Pompe's disease are presented, namely, signs of a cardiomyopathy with skeletal hypotonia and a characteristic ECG with a short PR interval and high voltage QRS complexes. Glycogen storage disease is confirmed by staining tissue such as lymphocytes, liver, or skeletal muscle with PAS, and the same tissues may be examined for glycolytic enzyme activity in order to characterize the type of glycogen storage disease present.