Biomarker for Pompe Disease AN INTERNATIONAL, MULTICENTER, EPIDEMIOLOGI-CAL PROTOCOL

Brief Summary

Detailed Description

Pompe disease is a rare (estimated at 1 in every 40,000 births), inherited and often fatal disorder that disables the heart and muscles. It is caused by mutations in a gene that encodes an enzyme called alpha-glucosidase (GAA). Normally, the body uses GAA to break down glycogen, the long-term storage form of sugar, into glucose, which the body can utilize to gain energy. But in Pompe disease, mutations in the GAA gene reduce or completely eliminate the activity of this essential enzyme. Excessive amounts of glycogen accumulate everywhere in the body, but the cells of the heart and skeletal muscles are the most seriously affected. Re-searchers have identified up to 70 different mutations in the GAA gene that cause the symptoms of Pompe disease, which can vary widely in terms of age of onset and severity. The severity of the disease and the age of onset are related to the degree of enzyme deficiency. Early onset (or infantile) Pompe disease is the result of complete or near complete deficiency of GAA. Symptoms begin in the first months of life, with feeding problems, poor weight gain, muscle weakness, floppiness, and head lag. Respiratory difficulties are often complicated by lung infections. The heart is grossly enlarged. More than half of all infants with Pompe disease also have enlarged tongues. Most babies with Pompe disease die from cardiac or respiratory complications before their first birthday. 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. 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. New methods, like mass-spectrometry give a good chance to characterize in the blood (plasma) of affected patents specific metabolic alterations that allow to diagnose in the future the disease earlier, with a higher sensitivity and specificity. Therefore it is the goal of the study to develop new biochemical markers from the plasma of the affected patients helping to benefit the patient by an early diagnose and thereby with an earlier treatment.

Primary Outcomes

Secondary Outcomes

• Testing for clinical robustness, specificity and long-term stability of the biomarker(36 months)