Our primary aim is to increase our knowledge on the functions of dystrophin isoforms in the CNS in order to reveal the causative mechanisms underlying brain co-morbidities in DMD and BMD. We will comprehensively describe the brain endophenotypes in the largest cohort of DMD and BMD patients to identify adequate and validated clinical screening tools, with recommendations for clinical management, that will be disseminated to the national and international clinical networks via the ERNs. We will determine which aspects of the abnormal dystrophic mouse behaviours can be reversed by postnatal dystrophin restoration. We also aim to identify robust outcome measures that will lay down the foundation for future treatments targeting the deficiency of dystrophin in the brain of DMD boys.