GAA disease, more commonly known as Pompe disease, is a genetic disorder caused by a deficiency of the enzyme acid alpha-glucosidase (GAA). This enzyme is crucial for breaking down glycogen, a complex sugar stored in the body's cells for energy.
Here's a breakdown:
- The Core Problem: A shortage or absence of the GAA enzyme.
- What Happens Without Enough GAA? Glycogen accumulates abnormally within cells, particularly in muscles and organs.
- The Result? This buildup damages the affected tissues, leading to a range of symptoms, varying in severity depending on the age of onset and the amount of residual enzyme activity.
Pompe disease is classified as a glycogen storage disease. These diseases are characterized by the body's inability to properly process glycogen. Pompe disease specifically is caused by mutations in the GAA gene.
The symptoms of Pompe disease can vary widely, but some common manifestations include:
- Muscle Weakness (Myopathy): Progressive muscle weakness is a hallmark of the disease.
- Respiratory Problems: Weakness of the respiratory muscles can lead to breathing difficulties and increased susceptibility to respiratory infections.
- Cardiomyopathy: In infantile-onset Pompe disease, the heart is often significantly enlarged and weakened.
- Feeding Difficulties: Infants with Pompe disease may have trouble feeding and gaining weight.
There are generally two main types of Pompe disease:
- Infantile-Onset Pompe Disease: This form typically presents within the first few months of life and is the most severe. Without treatment, it often leads to death within the first year.
- Late-Onset Pompe Disease: This form can present anytime from infancy to adulthood and is generally less severe than the infantile form. The symptoms progress more slowly.
Treatment for Pompe disease primarily involves enzyme replacement therapy (ERT), where the missing or deficient GAA enzyme is replaced with a manufactured version. ERT can help to slow the progression of the disease and improve muscle function and overall survival. Other supportive therapies, such as respiratory support and physical therapy, may also be necessary.
