Pompe disease

What is Pompe disease?

Pompe disease is an inherited disorder caused by the buildup of a complex sugar called glycogen in the body's cells. The accumulation of glycogen in certain tissues, especially muscles, impairs their ability to function normally.

One type of Pompe disease, known as infantile onset, begins within a few months of birth. Infants with this disorder typically exhibit symptoms such as muscle weakness (myopathy), poor muscle tone (hypotonia), an enlarged liver and heart, and heart failure. Affected infants may also have poor feeding, failure to gain weight and grow at the expected rate (failure to thrive), and breathing problems. Most infants with Pompe disease cannot hold up their heads or move normally. As the disease progresses, swallowing may become difficult and the tongue may become abnormally enlarged (macroglossia). Most children with this form of Pompe disease do not survive beyond the age of 2.

Other forms of Pompe disease are known as late onset and may not show signs and symptoms until childhood, adolescence, or adulthood. Late-onset Pompe disease is usually milder than the infantile-onset form of this disorder. Most individuals experience progressive muscle weakness, especially in the legs and the trunk, including the muscles that control breathing.

How common is Pompe disease?

Pompe disease affects about 1 in 40,000 people.

What genes are related to Pompe disease?

Mutations in the GAA gene cause Pompe disease.

The GAA gene provides instructions for producing an enzyme called acid alpha-glucosidase (commonly called acid maltase). This enzyme is active in lysosomes, which are structures that serve as the cell's recycling center. The enzyme normally breaks down glycogen into a simpler sugar called glucose, which is the main energy source for most cells. Mutations in the GAA gene prevent acid alpha-glucosidase from breaking down glycogen, allowing it to build up in the body's cells. Over time, this buildup damages cells throughout the body, particularly muscle cells.

How do people inherit Pompe disease?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

External Resources

Pompe's Disease Page - Kevin O'Donnell's Web site. Father of an affected child provides information about this glycogen storage disease.

United POMPE Foundation - Pompe Disease support group. Assisting families with unmet medical costs.

Pompe.com - For individuals and families who are living with Pompe disease, and for the health care professionals who treat them. From Genzyme Corporation.