Pompe disease (Glycogen Storage Disease Type II, acid maltase deficiency) is a lysosomal storage disorder with a varied phenotype. The severe form is characterised by a severe cardiac and skeletal myopathy in infants (Infantile Pompe disease). If this is suspected, diagnosis should be made urgently including assessment of CRIM status. This is particularly important as treatment is available for this condition.
The adult form (late onset Pompe Disease) is notable for slowly progressive myopathy, affecting proximal and spinal muscles as well as the diaphragm. Cardiac disease in these patients is usually not present. CKs in both types may be normal to mildly elevated. An intermediate phenotype also exists.
Muscle biopsy reveals an accumulation of glycogen.