This study will make use of the existing NorthStar network to collect a wider range of clinically relevant data from paediatric and adult DMD patients, to describe more completely the natural history of the disease in different domains and across different life stages and disease phases. Data will be collected using assessment techniques and outcome measures appropriate to the major phases of the disease, and which are in some cases not currently part of the standard of care for DMD in the UK. The National Neuromuscular Database will continue to be used to collect and store these data. This study will allow the network to continue to describe the current natural history in DMD prospectively, with more robust subject ascertainment and completeness. This will help meet the current need for contemporary natural history data for the evaluation of new therapies, and further research in DMD.