 Inclusion criteria will be limited to those over 18 years of age, with a genetic confirmation of DM1 who are able to provide informed consent. This unrestrictive approach will enable assessment of a true cross-section of the population, including those with congenital, childhood and adult onset. Two substudies will be open to a subset of patients, one assessing muscle through MRI and on focussing on sleep and fatigue. Additional restrictions may be in place to ensure the safety of the participants during these studies. 