Idursulfase enzyme replacement therapy in an adult patient with severe Hunter syndrome having a novel mutation of iduronate-2-sulfatase gene.

Mucopolysaccharidosis II (Hunter syndrome), a lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS), has variable clinical phenotypes. Total by nearly 400 different mutations have been identified in IDS gene from patients with Hunter syndrome. Herein, we reported a patient who has a novel mutation in IDS gene with a severe clinical phenotype. Genetic analysis of the IDS gene revealed a novel 1-bp deletion in position c.1053T in exon 8 and resulting in a frameshift with a premature stop codon. Enzyme replacement therapy (ERT) using idursulfase (Elaprase®) was conducted to the patient and it improved hepatosplenomegaly, white blood cells and platelets number, and decreased the level of urinary glycosaminoglycan. ERT was proved to be effective at least in part in even an adult patient with severe type of Hunter syndrome.