Inclusion Criteria:

• Signed informed consent by a parent or legal guardian after the nature of the study has been explained and prior to any research-related procedures
• Willing and able to comply with all study procedures
• Equal to or greater than 36 weeks estimated gestational age by physical exam at birth
• Has a diagnosis of MPS VI based on a documented prenatal diagnosis or fibroblast or leukocyte N-acetylgalactosamine 4-sulfatase (ASB) enzyme activity level of less than 10% of the lower limit of the normal range of the measuring laboratory
• Is less than one year of age
• Has no evidence of skeletal dysplasia based on physical exam

Exclusion Criteria:

• Perceived to be unreliable or unavailable for study participation or, if under the age of 18, have parents or legal guardians who are perceived to be unreliable or unavailable
• Use of any investigational drug within 30 days prior to screening, or requirement for any investigational agent prior to completion of all scheduled study assessments
• Concurrent disease or condition that would interfere with study participation or safety (i.e., has previously undergone hematopoietic stem cell transplantation such as bone marrow or cord blood transplantation, or major organ transplantation)
• Any condition that, in the view of the PI, renders the subject at high risk from treatment compliance and/or completing the study
• Has known hypersensitivity to Naglazyme
• Has previously received Naglazyme