A Study to Evaluate the Safety, Tolerability and Efficacy of BMN 110 in Subjects With Mucopolysaccharidosis IVA

Inclusion Criteria: * Documented history of reduced GALNS activity relative to the normal range of the laboratory performing the assay, or documented result of molecular genetic testing confirming diagnosis of MPS IVA. * Willing and able to provide written, signed informed consent, or in the case of subjects under the age of 16 years, provide written assent (if required) and written informed consent by a legally authorized representative after the nature of the study has been explained, and prior to any research-related procedures. * Between 5 and 18 years of age, inclusive. * Sexually active subjects must be willing to use an acceptable method of contraception while participating in the study. * Females of childbearing potential must have a negative pregnancy test at Screening and be willing to have additional pregnancy tests during the study. * Willing to perform all study procedures as physically possible. Exclusion Criteria: * Previous hematopoietic stem cell transplant (HSCT). * Has known hypersensitivity to BMN 110 or its excipients. * Pregnant or breastfeeding at Screening or planning to become pregnant (self or partner) at any time during the study. * Use of any investigational product or investigational medical device 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, including, but not limited to, symptomatic cervical spine instability. * Any condition that, in the view of the Principal Investigator (PI), places the subject at high risk of poor treatment compliance or of not completing the study.