Inclusion Criteria:  Subjects with DMD or BMD based on genetic testing. Control subjects are unknown to have any other muscular dystrophy by history and may have had no genetic testing. Able to provide informed consent or assent for participation in the study. Demographic characteristics for biofluid collection: Males age 5 years and older with DMD or BMD; males and females ages 18 years and older without muscular dystrophy.  Exclusion Criteria:  Medical history of any of the following: State of immunosuppression; coagulopathy; pre-existing liver or kidney disease; documented HIV positive; documented hepatitis B and/or C positive. Use of anti-platelet drugs within 7 days prior to blood draw; use of anticoagulants within 60 days prior to blood draw. Inability or unwillingness of the subject to give written informed consent.