MBNL2 and myotonic dystrophy type 1: Myotonic dystrophy type 1 (DM1) is characterized by multi-systemic disorders including muscle weakness and wasting.1, 2, 3 In DM1, the expansion of tri-nucleotide CUG repeats results in the formation of stable hairpin structures and sequestration of splicing regulators, such as muscleblind-like proteins and CUG-binding proteins, required for pre-mRNA alternative splicing.