Extension Study of BMN 044 in Duchenne Muscular Dystrophy (DMD)

Inclusion Criteria: * Subjects previously treated with BMN 044 or a comparator treatment in a BMN 044 Sponsored Study or Investigator Initiated Trial and who are not eligible for another ongoing BMN 044 study. * Continued use of glucocorticosteroids for a minimum of 60 days prior to study entry with a reasonable expectation that the subject will remain on glucocorticosteroids for the duration of this study. * Willing and able to comply with all study requirements and procedures. * Willing and able to provide written, signed informed consent, or in the case of subjects under the age of 18 years(or 16 years, depending on the region), 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 the conduct of any research-related procedures. Exclusion Criteria: * Subjects who have previously been treated with BMN 044 who had a serious adverse experience or met safety stopping criteria, that remains unresolved, which in the opinion of the Investigator could have been attributable to BMN 044. * History of significant medical disorder which may confound the interpretation of safety data * Acute illness within 4 weeks prior to the first dose of BMN 044 (Week 1) which may interfere with the measurements. * Symptomatic cardiomyopathy. * Baseline aPTT above the upper limit of normal (ULN). * Baseline platelet count below the lower limit of normal (LLN). * Use of anti coagulants, anti thrombotics or anti platelet agents within 28 days of the baseline visit. * Prior use of any investigational product (other than BMN 044) or investigational medical device must be discussed with the Medical Monitor prior to screening. * Current or history of drug and/or alcohol abuse.