Glycogen storage disease type II

Glycogen storage disease type II, abbreviated GSD-II and also called Pompe disease, is an autosomal recessive metabolic disorder that damages muscle and nerve cells throughout the body. It formerly went by the names GSD-IIa and limb-girdle muscular dystrophy 2V. The disease is caused by a deficiency of the lysosomal enzyme acid alpha-glucosidase, so glycogen accumulates inside lysosomes and cannot be broken down. The result is progressive muscle weakness that affects the heart, skeletal muscles, liver and nervous system. Together with Danon disease it is one of only two glycogen storage diseases characterised by a defect in lysosomal metabolism. It was first identified in 1932 by the Dutch pathologist Joannes Cassianus Pompe, making it the first glycogen storage disease to be discovered.