Types of Pompe Disease
Classic Infantile-Onset Pompe Disease
In classic infantile-onset Pompe disease, symptoms such as cardiomyopathy or disease of the heart muscle appear before a baby reaches 12 months of age. In some cases, symptoms of classic infantile-onset Pompe disease can be recognized before a baby is born, but the disease is often diagnosed in the first few months of life.
Non-classic Infantile-onset Pompe Disease
Non-classic infantile-onset Pompe disease typically develops within the first year of life, but later than the classic form. In this form of the disorder, a person has inherited GAA gene copies that produce very little or no working acid alpha-glucosidase. Symptoms are usually less severe than in classic infantile-onset Pompe disease.
Late-onset Pompe Disease
People with late-onset Pompe have higher GAA enzyme levels than are found in the infantile-onset forms of this disease. In this form, symptoms develop during late childhood or adulthood, with muscle weakness often appearing first. People with late-onset Pompe have higher GAA enzyme levels than are found in the infantile-onset types, but generally less than 40% of normal levels.