Infantile, or early onset, is noticed shortly after birth. Symptoms include severe lack of muscle tone, weakness, an enlarged liver, and an enlarged heart, feeding problems, poor weight gain, floppiness and head lag. Mental function is not affected. Development appears normal for the first weeks or months but slowly declines as the disease progresses. Swallowing may become difficult and the tongue may protrude and become enlarged.
Infantile Pompe is the result of complete or near complete deficiency of GAA. Respiratory difficulties are often complicated by lung infections. Most babies with Pompe disease die from cardiac or respiratory complications before their first birthday.
Symptoms of Adult Onset Pompe
Adult onset symptoms also involve generalized muscle weakness and wasting of respiratory muscles in the trunk, lower limbs, and diaphragm. Many patients report respiratory distress, headache at night or upon waking, diminished deep tendon reflexes, and proximal muscle weakness, such as difficulty in climbing stairs. Intellect is not affected. A small number of adult patients live without major symptoms or limitations. The heart may be involved but it will not be grossly enlarged. A diagnosis of Pompe disease can be confirmed by screening for the common genetic mutations or measuring the level of GAA enzyme activity in a blood sample - a test that has 100 percent accuracy. Once Pompe disease is diagnosed, testing of all family members and consultation with a professional geneticist is recommended. Carriers are most reliably identified via genetic mutation analysis.
Late onset (or juvenile/adult) Pompe disease is the result of a partial deficiency of GAA. The onset can be as early as the first decade of childhood or as late as the sixth decade of adulthood. The primary symptom is muscle weakness progressing to respiratory weakness and death from respiratory failure after a course lasting several years.