Glycogen storage disease type II (also called Pompe disease or acid maltase deficiency) is a neuromuscular, autosomal recessive metabolic disorder in the family of lysosomal storage diseases caused by a deficiency in the enzyme Acid alpha-glucosidase (EC 3.2.1.20), which is needed to break down glycogen—a long, branched glucose polymer and stored form of sugar used for energy. It is the only glycogen storage disease with a defect in lysosomal metabolism and was the first glycogen storage disease to be identified, in 1932.
The build-up of glycogen causes progressive muscle weakness (myopathy) throughout the body and affects various body tissues, particularly in the heart, skeletal muscles, liver and nervous system.
The disease is named after Johann Pompe, who characterized it in 1932.
