What is Pompe disease?
Pompe disease is a metabolic muscle disorder first described in 1932 by Dr JC Pompe. It is a rare neuromuscular genetic disorder that occurs in babies, children, and adults who inherit a defective gene from each of their parents. The disorder has a number of synonyms, the most common are:
- Acid Maltase Deficiency
- Glycogen Storage Disease Type II (GSD II)
What are the symptoms of Pompe disease?
Progressive muscle weakness is the most common symptom of both the infantile-onset and the late-onset forms of Pompe disease. The muscles most often affected are those used for breathing and mobility. In infants, the heart muscle is often severely affected.
Where breathing muscles are affected the patient might suffer from headaches in the morning and an inability to concentrate during the day.
What causes Pompe disease?
In people with Pompe disease, there is a defect in a gene that is responsible for making an enzyme called acid alpha-glucosidase (GAA). Enzymes are proteins that do specific jobs to help keep the cells in the body working normally.
In people with Pompe disease, the GAA enzyme is either missing or in short supply. The job of acid alpha-glucosidase is to break down excess glycogen, a form of sugar stored in muscle cells throughout the body. The missing enzyme leads to a build up of glycogen in the lysosomes of cells. This is why Pompe disease is also referred to as a Lysosomal Storage Disease (LSD).
How is Pompe disease diagnosed?
A conclusive diagnosis of Pompe disease generally requires an enzyme assay test that demonstrates that the patient has deficient enzyme (acid alpha-glucosidase, "GAA") activity. This is determined by performing tests on a tissue (muscle, skin) or blood sample to verify that the patient's GAA enzyme activity is low or absent. Infantile-onset patients generally display less than 1% of the normal enzyme activity levels in skin cells; late-onset patients generally display less than 40% of the normal enzyme activity levels in skin cells.
Is there any treatment?
An Enzyme Replacement Therapy (ERT), developed by The Genzyme Corporation (www.pompe.com) is now available to patients around the world. The enzyme replacement is called Myozyme and is available in Malaysia.
Clinical trials have proven the benefits of Myozyme and it has been approved for all patients (infants, juveniles and adults) worldwide.