News in Hunter syndrome diagnosis and therapy

Abstract

Mucopolysaccharidosis type II (Hunter syndrome, OMIM309900) is an inherited disease caused by defi ciency of the enzyme iduronate- 2-sulfatase. Iduronate-2-sulfatase defi ciency leads to the accumulation of glycosaminoglycans (GAG) in the tissues of the musculoskeletal system, visceral organs and central nervous system causing progressive damage. Diagnosis of mucopolysaccharidosis type II is based on early recognition of clinical signs and low enzyme activity necessary for diagnosis confi rmation. Improvement of diagnostic techniques has provided fast detection of enzyme activity and their use in screening of patients at risk. Until now, enzyme replacement therapy is a proven and eff ective treatment option. Enzyme replacement therapy leads to an increase in the quality of life, and a decrease of visceromegaly and urinary GAG excretion. As enzyme replacement therapy does not cross the bloodbrain barrier, there is no infl uence on the central nervous system. Encouraging reports of stem cell transplantation and attempts of substrate reduction therapy are also described, however, requiring further investigation.