Enzyme-Replacement Therapy in Mucopolysaccharidosis I

Mucopolysaccharidosis I is a lysosomal storage disease caused by a deficiency of α-L-iduronidase, an enzyme that cleaves the terminal α-l-idu-ronic acid residues in the glycosaminoglycans heparan sulfate and dermatan sulfate. 1 , 2 The deficiency blocks the degradation of these glycosaminoglycans, which accumulate in lysosomes. Mucopolysaccharidosis I has a wide spectrum of clinical severity and has been subdivided into three syndromes: Hurler's syndrome (severe), Hurler–Scheie syndrome (intermediate), and Scheie's syndrome (mild). Patients with Hurler's syndrome have many medical problems, including progressive developmental delay, corneal clouding, airway obstruction, cardiac disease, hepatosplenomegaly, and severe joint restriction, and most die by the age of 10 . . .