The Mucopolysaccharidosis I (MPS I) Registry is an ongoing, observational database that tracks the outcomes of patients with MPS I. The data collected by the MPS I Registry will provide information to better characterize the natural history and progression of MPS I as well as the clinical responses of patients receiving enzyme replacement therapy, such as Aldurazyme (Recombinant Human Alpha-L-Iduronidase), or other treatment modalities. The objectives of the Registry are: * To evaluate the long-term effectiveness and safety of Aldurazyme® (laronidase) * To characterize and describe the MPS I population as a whole, including the variability, progression, and natural history of MPS I * To help the MPS I medical community with the development of recommendations for monitoring patients and reports on patient outcomes to optimize patient care