Pompe Disease
Description
Pompe disease, also known as glycogen storage disease type II (GSD II), is a rare genetic disorder characterized by the deficiency of the enzyme acid alpha-glucosidase (GAA). This enzyme is crucial for breaking down glycogen, a stored form of energy, in the body‘s cells, particularly in muscles. Without sufficient GAA, glycogen accumulates in muscle cells, leading to muscle weakness, fatigue, and eventual breathing difficulties.
Genes Involved
Pompe disease is caused by mutations in the GAA gene, located on chromosome 17. This gene provides instructions for making the GAA enzyme. Mutations in this gene can lead to a complete or partial deficiency of the enzyme, resulting in the accumulation of glycogen in the body‘s cells.
Recognizing the Signs and Symptoms
The symptoms of Pompe disease vary depending on the age of onset and the severity of the GAA deficiency. Infants with Pompe disease often present with muscle weakness, feeding difficulties, and delayed motor development. In later-onset Pompe disease, symptoms may include progressive muscle weakness, difficulty breathing, and fatigue. Other possible signs and symptoms include:
Causes
Pompe disease is caused by a genetic mutation in the GAA gene, which is responsible for producing the enzyme acid alpha-glucosidase. This enzyme is essential for breaking down glycogen, a stored form of energy, in muscle cells. Without sufficient GAA, glycogen accumulates in muscle cells, leading to muscle weakness and other symptoms.
Inheritance/recurrence risk
Pompe disease is inherited in an autosomal recessive pattern. This means that a person must inherit two copies of the mutated gene, one from each parent, to develop the disease. If both parents carry one copy of the mutated gene, there is a 25% chance that their child will inherit two copies and develop Pompe disease, a 50% chance that their child will inherit one copy and be a carrier, and a 25% chance that their child will not inherit the mutated gene. Individuals with only one copy of the mutated gene are typically unaffected.
