Pompe's disease has a birth prevalence of about 1 in 40 000 in the USA and some 5000–10 000 people are thought to be affected worldwide. The main difference between the infantile and the late-onset forms is the presence of cardiomyopathy in the infantile form. The cause is a mutation (>200 have been described) in the autosomal recessive acid α-glucosidase …