Defining Endpoints in Becker Muscular Dystrophy

Prior treatment

• Use of chronic corticosteroids at baseline, defined as greater than 6 months of chronic use, will be limited to 20% of the overall population
• Loss of ambulation prior to age 16
• Use of chronic corticosteroids, defined as greater than 6 months of chronic use, will be limited to 20% of the overall population

Other illness

• Any other illness that would interfere with the ability to undergo safe testing or would interfere with interpretation of the results in the opinion of the site investigator.

Age

• For ages 6-12
• Under the age of 6 at time of enrollment
• For MR Cohort: Have contraindications to MRI or MRS (e.g., non-MR compatible implanted medical devices or severe claustrophobia)
  • For ages 13 and older
• Subjects aged 13-16 only: time to rise \>10 seconds

Other

• Out of frame dystrophin mutation
• Non-ambulatory, defined as the inability to walk 10 meters without assistive device (excluding orthotics)
• \>16 hours of ventilatory support
• Less than 30% of the overall population will be non-ambulatory, defined as the inability to walk 10 meters without assistive device (excluding orthotics)
• \>16 hours of ventilatory support
• For MR Cohort: Have contraindications to MRI or MRS (e.g., non-MR compatible implanted medical devices or severe claustrophobia)

• For ages 6-12
• Clinically affected (defined as weakness on bedside evaluation in a pattern consistent with BMD)
• Genetic confirmation of an in-frame dystrophin mutation
• Ambulatory
• Willing and able to give informed consent and follow all procedures and requirements
  • For ages 13 and older
• Clinically affected (defined as weakness on bedside evaluation in a pattern consistent with BMD)
• Genetic confirmation of a dystrophin mutation
• Willing and able to give informed consent and follow all procedures and requirements
  • For participants in the MRI substudy:
  • 1\. Ambulatory, defined as able to walk 10 meters without assistive devices (orthotics allowed)