There are now more than 70 separate lysosomal storage diseases described, and as a group they are not very rare. Approximately 1 in 6,000-7,000 children born will have lysosomal storage disease. It is a group of mucopolysaccharidoses, forming a group of lysosomal storage disorders caused by defective degradation of a particular group of macromolecules named glycosaminoglycans, or abbreviated as GAGs.