The purpose of this phase I/II, multicenter, safety trial is to study MYO-029 in adult patients with muscular dystrophy.

Inclusion Criteria:

• Written informed consent.
• Confirmed clinical and molecular diagnosis of Becker Muscular Dystrophy (BMD), Facioscapulohumeral Muscular Dystrophy (FSHD), or Limb-Girdle Muscular Dystrophy (LGMD)
• Independently ambulatory

Exclusion Criteria:

• Patients with certain clinical conditions
• Patients using steroids or other medications with the potential to affect muscle function
• History of sensitivity to monoclonal antibodies or protein pharmaceuticals
• Pregnant or lactating women.