An Ambispective Natural History Study in Myotonic Dystrophy Patients Linking Retrospective Data Captured From the DM-Scope Registry With a Prospective 24-month Follow-up Period

This natural history observational study is being conducted to follow patients with DM1 or DM2 over a 2 year period to study the presence of myotonia, how it's perceived and its impact on patients quality of life. This study will be conducted at 6 study sites located in France.100 Patients will be recruited from the DM Scope Registry only. The study involves two parts. Part 1 will look back up to 18 months of past medical history that is already available from the DM Scope Registry. Part 2 will follow the same patients for 24 months, with study visits at Day 1 (Baseline), 12 months and 24 months. The goal is to better understand how myotonia symptoms and complications such as heart and other systemic problems develop and change over time. A smaller, sub-study will take place at one site, using new exploratory methods in about 40 patients with DM1 who are also part of the Track DM Study.