MBNL1 and myotonic dystrophy type 1: The current model of disease progression derives from the strong interaction of expanded CUG-RNA with splicing regulators such as the muscleblind-like proteins (MBNL1–MBNL3) and CUG-BP Elav-like family member 1 (CELF1), key proteins involved in DM1 pathophysiology (Udd and Krahe, 2012).