A Dose-optimization Study of Aldurazyme® (Laronidase) in Patients With Mucopolysaccharidosis I (MPS I) Disease

Inclusion Criteria: * Have a documented diagnosis of MPS I, confirmed by measurable clinical signs and symptoms of MPS I, and a documented fibroblast or leukocyte α-L-iduronidase enzyme activity level of less than 10% of the lower limit of the normal range of the measuring laboratory. * Weigh at least 12.5 kg. * Have serum creatinine and blood urea nitrogen (BUN) values within age appropriate normal ranges. * Provide signed, written informed consent prior to any protocol-related procedures being performed. Consent of a legally authorized guardian(s) is (are) required for patients under 18 years. If the patient is under 18 years old and can understand the consent, written informed consent will be required from both the patient and the authorized guardian(s). Exclusion Criteria: * Have previously received Aldurazyme® (laronidase). * Have a suspected hypersensitivity to Aldurazyme® (laronidase) or known hypersensitivity to components of the infusion solution. * Have previously undergone hematopoietic stem cell transplantation (HSCT; i.e., from bone marrow \[BMT\], peripheral blood, or umbilical cord blood) or other major organ transplantation. * Have a medical condition, serious inter-current illness, or other extenuating circumstance that may interfere with study compliance including all prescribed evaluations and follow-up activities, except the 6MWT. (Note: All patients may not be capable of performing the 6MWT due to age and/or maturity level. Exemption from performing th…