Pompe Disease

Also known as Glycogen Storage Disease Type II (GSD II)

Characteristics

Pompe disease is a hereditary condition that can manifest at any age, with significant variation in severity. The most severe form occurs in infants shortly after birth. These babies experience severe muscle weakness and heart problems soon after birth. Without enzyme replacement therapy, they do not survive beyond their first year.

Older children and adults develop a slower-progressing form of the disease. They often experience progressive limb-girdle muscle weakness and/or pronounced weakness of the respiratory muscles. The heart is typically not affected. Over time, skeletal muscle weakness worsens, eventually preventing patients from standing or walking independently. Respiratory muscle involvement may lead to the need for mechanical ventilation.

Each year, 5–8 new cases of Pompe disease are diagnosed in the Netherlands. In total, approximately 200 people in the Netherlands live with this condition.

Cause

Pompe disease is caused by a metabolic defect in the muscles due to a mutation in the genetic code for alpha-glucosidase. This mutation impairs the function of the alpha-glucosidase enzyme, preventing the breakdown of glycogen. As a result, glycogen accumulates in the lysosomes of muscle cells, disrupting their normal function and leading to progressive muscle weakness.

Treatment

Pompe disease is the first hereditary muscle disease with an available treatment. Enzyme replacement therapy (ERT) involves delivering the missing alpha-glucosidase enzyme into the bloodstream via intravenous infusion. This therapy aims to restore enzyme levels in muscle cells and halt further damage. Patients with Pompe disease visit Erasmus MC every two weeks for treatment. Erasmus MC houses the world’s largest Pompe center.