Abstract
The most severe form of Mucopolysaccharosidosis type I (MPS-I), Hurler syndrome, presents with progressive respiratory, cardiac and musculoskeletal symptoms and cognitive deterioration. Treatment includes enzyme replacement therapy (ERT) and/or hematopoietic stem cell transplantation (HSCT). We describe the case of an 8-year old boy with MPS-I, homozygous for W402X, treated at 10 months of age with HSCT and after failure of the transplant, with ERT during 2 years showing good results, including a positive neuropsychological development.