A Natural History Study In Chinese Male Patients With Duchenne Muscular Dystrophy

This is a multicenter, prospective, single cohort study designed to describe the natural history of DMD in Chinese male patients. A total of approximately 330 subjects will be enrolled with the target number of subjects in each group as below:

• Group 1, Ambulatory subjects aged <6 years, approximately 100 subjects;
• Group 2, Ambulatory subjects aged >=6 years, approximately 180 subjects;
• Group 3, Non-ambulatory subjects, approximately 50 subjects. Subjects will visit sites every 6 months. Each subject will be observed for at least 24 months. All subjects will remain enrolled until the study completion date, such that some will have data collected after Month 24. Subjects, who complete Visit 5/Month 24 at least 6 months prior to study completion, will be asked to complete an additional visit at Month 30.

Inclusion Criteria:

1. Chinese male patients with any age, diagnosed with DMD. Diagnosis must be confirmed in subject's medical history and by genetic testing obtained during routine clinical care for diagnostic purposes as reported from an appropriate regulated laboratory using a clinically validated genetic test (genetic testing is not provided by the sponsor).
2. Subjects who are >=4 years old must be receiving glucocorticosteroids for a minimum of 6 months prior to signing informed consent. There should be no significant change (<0.2 mg/kg) in dosage or dose regimen (not related to body weight change) for at least 3 months immediately prior to signing the informed consent. Subjects who are aged >4 years will be exempt from this requirement; those not taking GC will be eligible if the initiation of GC treatment in these subjects is considered inappropriate in the opinion of Investigators.

Exclusion Criteria:

1. Any injury which may impact functional testing. Previous injuries must be fully healed prior to consenting. Prior lower limb fractures must be fully healed and at least 3 months from injury date.
2. Presence or history of other musculoskeletal or neurologic disease or somatic disorder not related to DMD including pulmonary, cardiac, and cognitive diseases.
3. Subjects >=4 years old who have not completed the varicella vaccination.
4. Participation in other studies involving investigational drug(s) for a minimum of 90 days prior to signing the informed consent and/or during study participation.