This booklet was written by Professor Dr Francois Eyskens of the PCMA vzw  the metabolic laboratory  and the Center of Inherited Metabolic Diseases at the University of Antwerp  Belgium It focuses on the understanding  diagnosis and treatment of young people with the rare diseases  MPS (or mucopolysaccharidoses)  as well as looking into the various types of Gaucher disease  a lysosomal storage disorder