Stem Cell based Gene Therapy for Pompe's Disease

According to the European Organization for Rare Disease (EURORDIS), about 30 million people in Europe are affected by one of the 6,000-8,000 rare diseases that are currently known. The number of people affected in the European Union amounts to 6-8% of the total population. Most rare diseases (80%) are genetically determined, and a small percentage of those represent “lysosomal storage disorders (LSDs)”. They are caused by protein deficiencies that affect the function of an intracellular organelle called “lysosome”. Most LSDs are monogenic disorders that result from a single genetic defect leading to the absence or dysfunction of a single protein -usually an enzyme- that can, however, interfere with more than one metabolic or catabolic pathway. This group of LSDs consists of approximately 50 different metabolic diseases and displays a broad variety of disease manifestations depending on the functional (enzyme) deficiency, the particular pathway involved, and the kind of resulting lysosomal storage products. The overall incidence of LSDs is approximately 1: 5,000, however, the incidence of individual diseases is much more rare. For example the incidence of Pompe’s disease and Fabry’s disease is 1:40,000. The pattern of inheritance of almost all LSDs is autosomal recessive. A few of them are X-linked inherited. With their content of approximately 50 lysosomal enzymes (mostly hydrolases) lysosomes are able to degrade virtually every cellular substance and play a crucial role in cellular renewal via recycling. The products to be recycled enter the lysosomes through processes of (micro) autophagy, and endocytosis.