Pompe’s disease is an inherited metabolic illness, caused by an inherited deficiency of an enzyme, called acid a-glucosidase. Acid a-glucosidase is a protein that breaks down glycogen (a chain of glucose molecules) into glucose (a single molecule), in a specific compartment of the cell, the lysosome. The lysosome thus takes care of the removal and recycling of substances in the cell. The deficiency of acid a-glucosidase results in glycogen accumulation in the lysosome (lysosomal storage). This happens mainly in muscle cells, where under normal circumstances a lot of glycogen is stored and recycled thereafter. The lysosomal storage of glycogen causes gradual destruction of muscle cells, which results in loss of contraction capacity of the muscle cells, and finally in the loss of muscle function(s). Pompe’s disease can become apparent at any age. Complete defi ciency of the enzyme results in the severe and quickly progressive classic form of Pompe’s disease, characterized by generalized muscle weakness and an enlarged heart. Symptoms present within the first 3 months of life. Loss of muscle strength prevents children of achieving major developmental milestones such as sitting, standing and walking. The patients usually die within the first year of life due to insufficiency of the respiratory muscles and the heart. A partial deficiency of acid a-glucosidase causes a slowly progressive phenotype, involving mainly skeletal muscle. The first symptoms can occur in early childhood, but can also stay away until late adulthood. The disease presents itself as a proximal myopathy. Fatigue, ‘clumsiness’ and difficulty climbing stairs are often the first symptoms. Eventually patients may become wheelchair-dependent. The pulmonary function gradually decreases due to weakness of the respiratory muscles. Mechanical ventilation is often necessary, first during the night, sometimes also during daytime.

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Büller, Prof. Dr. H.A. (promotor), Pharming Genzyme LLC, Sophia Foundation for Scientific Research (SSWO)
H.A. Büller (Hans)
Erasmus MC: University Medical Center Rotterdam

Winkel, L. (2004, November 5). Enzyme Therapy in Non-classic Pompe’s Disease: Safety and efficacy of recombinant human a-glucosidase from milk of transgenic rabbits and from Chinese hamster ovary cells. Retrieved from http://hdl.handle.net/1765/7350