Role of the GAA enzyme
Under normal circumstances, the GAA enzyme is involved in breaking down glycogen (a large sugar molecule) into smaller sugars, which are then returned to the cell for use. When this enzyme is absent or does not work properly, carbohydrates accumulate. This is why Pompe disease is classified as a “storage disorder.” The buildup of carbohydrates affects all cells and tissues in the body, but it has the greatest impact on muscle tissue. Muscles become very weak, making it increasingly difficult for patients to move and, over time, to breathe.
Severe form: infantile Pompe disease
In the most severe form—known as infantile Pompe disease—patients will die within the first year of life if left untreated, due to enlargement of the heart muscle. Treatment with current therapies can correct the heart muscle abnormality and strengthen other muscles in these patients. However, after several years of treatment, muscle strength declines again. Even with treatment, the brain is affected in these children, and they gradually lose cognitive abilities.
Milder forms
There are also milder forms of Pompe disease. Patients with these forms often become wheelchair-dependent and require ventilatory support to breathe. In these patients, the heart and brain are not affected.
Current treatment: enzyme replacement therapy
Current treatment with enzyme replacement therapy has a significant impact for many patients. In some, disease progression is (almost) halted; in others, the course of the disease is substantially slowed. However, enzyme replacement therapy does not reach the brain.
New possibilities: gene therapy
Early research results from the gene therapy being developed by LentiCure suggest that this approach may reach the brain. Further research is needed to confirm these findings.
More information
For more information about the disease and the enzyme replacement therapy currently available, see for example:
Pompe disease – condition – Erasmus MC Sophia
Spierziekten Nederland: Pompe disease
