Pompe disease is a glycogen storage disease characterized by the buildup of glycogen due to a deficiency of α-1,4-glucosidase. This enzyme is responsible for glycogen hydrolysis. It is a lysosomal enzyme and therefore Pompe disease is regarded as a type of lysosomal disease as well. Lysosomal storage disease is a collective term for the various metabolic disorders due to defects in lysosomal function resulting in an abnormal accumulation of toxic materials in the cell.
Pompe disease is caused by a deficiency of, or a defective, lysosomal α-1,4-glucosidase. It is due to a mutation in the gene that codes for this enzyme. In humans, the gene is located on the long arm of chromosome 17. Pompe disease is inherited in an autosomal recessive pattern. This means that the individual has two copies of the defective gene and therefore manifests symptoms associated with the disease. A carrier of the disease would have only one copy of the defective gene and therefore may not show symptoms. The infantile form presents cardiomegaly, hypotonia, cardiomyopathy, muscle weakness, and respiratory distress. Late onset of the disease manifests as recurrent chest infections, hypotonia, muscle weakness, and difficulty in chewing and swallowing, and lacks cardiac involvement.
Even though the nonlysosomal glycogenolytic system is normal, glycogen still accumulates in the lysosomes in almost all tissues. Nevertheless, the condition has severe effects in skeletal and cardiac muscle leading to early mortality. Specific enzyme assay in muscle cells, leukocytes or amniocytes confirms the diagnosis.
The condition is named after Johann Cassianus Pompe, a 20th-century Dutch pathologist. He was the first to describe the disease in 1932.
- Pompe syndrome
- acid maltase deficiency
- glycogen storage disease type II