Mucopolysaccharidosis (MPS) is a group of lysosomal storage diseases caused by an inherited deficiency of an enzyme involved in the breaking down of glycosaminoglycans (mucopolysaccharides). Currently there are seven main forms of MPS and numerous subtypes. Different types of mucopolysaccharidosis have their own characteristics. But traditionally MPS is divided into two main phenotypes: the Hurler-like phenotype and the Morkquio-like phenotype. The Hurler-like phenotype is often accompanied by dementia, hepatosplenomegaly and peculiar apperance and facial features (elongated appearance of the head, low nasal bridge, prominent foreheads, flattened appearance of the face, short and stiff neck, and abnormal curvature of the lower spine). The Morkquio-like phenotype represents the attenuated form of MPS when patients do not have coarse facial features or mental retardation. Other common symptoms of MPS are disproportionately short trunk (dwarfism), visual impairment (corneal opacity, etc.), hearing impairment (hearing loss), heart and vascular diseases (arrhythmias, myocardial hypertrophy, heart valve diseases), respiratory system diseases.