Observational Study of Patients With Duchenne Muscular Dystrophy Theoretically Treatable With Exon 53 Skipping

Inclusion Criteria: * Diagnosis of Duchenne muscular dystrophy confirmed by at least genetic testing, theoretically treatable by exon 53 skipping. * Age between ≥ 12 and \<20 years old. * Non ambulant patients (i;e; inability to walk more than 10 meters without any of assistance). * Patients covered by a national health insurance scheme. * Signed informed consent. Exclusion Criteria: * Patient incapable of sitting upright in a wheelchair for at least one hour. * Patients with severe intellectual impairment preventing them from fully understanding the exercises to be performed. * Recent (less than 6 months ago) upper limb surgery or trauma This criteria is however no definitive. Patients who have undergone upper limb surgery or trauma may nonetheless be enrolled once the 6 month period is over. * Known immune deficiency. * Contraindications to NMR exams