Morquio syndrome (mucopolysaccharidosis type IV; MPS IV) is a mucopolysaccharide stor-age disease that exists in two forms (Morquio syndromes A and B) and occurs because of a deficiency of the enzymes N-acetyl-galactosamine-6-sulfatase and beta-galactosidase, respectively. A deficiency of either enzyme leads to the accumulation of mucopolysaccharides in the body, abnormal skeletal development, and additional symptoms. In most cases, individuals with Morquio syndrome have normal intelligence. The clinical features of MPS IV-B are less severe than those associated with MPS IV-A. Symptoms may include growth retardation, a prominent lower face, an abnormally short neck, knees that are abnormally close together (knock knees or genu valgum), flat feet, abnormal sideways and front-to-back or side-to-side curvature of the spine (kyphoscoliosis), abnormal development of the growing ends of the long bones (epiphyses) resulting in dwarfism, and/or a prominent breast bone (pectus carinatum) as well as bell shaped chest. Though the CNS and peripheral nerves are primarily not affected the bone defects may result in neurological symptoms such as spinal cord compression.