An X-linked disease caused by a deficiency of the enzyme iduronate sulphate sulfatase, which breaks down dermatan sulphate and heparen sulphate, two types of mucopolysaccharides (complex carbohydrates). Consequently, the mucopolysaccharides accumulate in the cells of the body and cause damage. Patients have the two types of sulfates in their urine and suffer from skeletal defects, retinitis pigmentosa (progressive blindness), skin lesions, progressive deafness, and heart problems. There are mild and severe forms of the syndrome and presently no cure. Symptoms are treated as they appear. Hunter’s syndrome is the most common of a number of related rare genetic mucopolysaccharide disorders. For more information, visit MPS II - Hunter Syndrome and The National Organization for Rare Disorders -- Hunter's Syndrome.