Hunter syndrome

Hunter syndrome, also known as mucopolysaccharidosis type II, is a rare inherited lysosomal storage disorder in which large sugar molecules called glycosaminoglycans accumulate in the body's tissues because of a missing or deficient enzyme, iduronate-2-sulfatase. Without this enzyme, heparan sulfate and dermatan sulfate build up progressively throughout the body rather than being broken down normally. Hunter syndrome is the only one of the mucopolysaccharidosis syndromes that follows an X-linked recessive pattern of inheritance, meaning it occurs almost exclusively in males.