The mucopolysaccharide storage disorders are progressive and vary widely in severity. All MPS children tend to have coarse facial features. All of them have, in some degree, skeletal involvement. In most children this involves joint changes with limitation of movement. In all of the MPS disorders, multiple organs are involved.
Several children have clouding of the cornea which leads to vision impairment.
Enlargement of the liver and spleen and involvement of the heart and blood vessels are frequent symptoms. Progressive mental retardation is present in some children, as well as umbilical and groin hernias, stunted growth, fluid on the brain, thickened skin, excessive hair growth, chronic runny nose, chronic ear infections causing hearing loss, and a projected life expectancy of ten to twenty years. As a result, the mucopolysaccharides are not completely broken down. The lysosomal enzymes in the ML disorders lack a phosphate group which is necessary for directing the enzymes into the lysosomes. Therefore, the mucopolysaccharide and lipid materials accumulate in the cells and tissues.