Zur Kenntnis mitigierter adulter Formen des Mangels an saurer Maltase (Morbus Pompe)

Summary

Acid maltase deficiency (glycogenosis type II; M. Pompe) exists in three different clinical forms:

• 1. Infantile course with rapid progressive myopathy and cardiac involvement. This form presents as a rule a fatal disease with death in early infancy.

• 2. Juvenile form characterized by progressive proximal myopathy beginning in the adolescence associated with only mild cardiomyopath.

• 3. Very rare adult cases showing a late onse myopathy without cardiac symptoms, but with development of a respiratory deficiency.

Two cases of the last mentioned type are described and compaired with the typical course of a juvenile form.

From the morphological point of view there are striking differences between these two forms of the disease. While in the case of juvenile onset myopathy marked vacuoles in most muscle fibers are detectable and an excessive accumulation of glycogen can be demonstrated, structural changes in late onset cases are slight and as a rule can be shown only in scattered fibers, whereas great areas of muscle tissue appear normal.

Biochemically, the juvenile form is characterized by a clearly elevated glycogen content in combination with a significantly decreased activity of acid maltase. Adult forms in contrast show only decreased enzyme activity without detectable glycogen elevation.

Possible causes for the different expression of the disease are discussed and diagnostic difficulties in the detection of late onset forms pointed out.