Pompe disease, also known as glycogen storage disease type II, is a rare genetic disorder caused by the deficiency of an enzyme called acid alpha-glucosidase (GAA). This deficiency leads to the accumulation of glycogen in various organs and tissues, primarily affecting the heart, skeletal muscles, and respiratory muscles. Pompe disease can manifest at different ages and severity levels, ranging from a rapidly progressive infantile form to a slower progressing late-onset form.