Mucopolysaccharide, MPS, diseases are inherited from healthy parents who have no idea they carry the genetic defect. The diseases are rare and life-threatening which cause severe progressive handicap, often both physical and mental. Victims of theses diseases are unable to produce certain enzymes necessary for the correct chemical changes to take place in their bodies, consequently complex sugars become stored in all types of connective tissue causing progressive damage. They appear normal at birth and by the time the disease manifests itself sufficiently to be recognized they are toddlers most of whom will die before reaching adulthood. There are six main types: Hurler's syndrome, Hunter's syndrome, Sanfilippo syndrome, Morquio syndrome and Maroteaux-Lamy syndrome and three associated diseases: mucolipidosis, fucosidosis and sialic acid disease.