RESUMO
Mucopolysaccharidosis type I or mucopolisacaridosis type I is a rare genetic disease, with a severe and fast multiorganic damage profile and fatal prognosis in the early years of age. It belongs to the lysosomal storage diseases (LSD) group pathologies. As an LSD, mucopolisacaridosis type I is due to the lack of the α-L-iduronidase enzyme. Enzyme replacement therapy (ERT) with laronidase is an effective treatment choice. It is available in Mexico since 2005. In the Hospital UMAE 25 of the Mexican Institute of Social Security (IMSS) in Monterrey, Nuevo Leon, Mexico, three patients have been treated and followed since 2006, with a close surveillance on their clinical evolution. The ERT with laronidase is expensive, relatively new and with little experience in Mexico, so there is a real need of knowing clinical evolution as well as overall treatment efficacy from baseline pre-treatment stage to date. Data on physical, functional and biochemical changes in these patients is presented.