Pathology due to expanded repeat RNA was first attributed in DM1, caused by a non-coding CUG repeat within the 3′UTR of the dystrophia myotonica-protein kinase (DMPK) gene, and DM2, caused by a non-coding CCUG repeat within an intron of ZNF9 (now called CNBP) [22], [23]. The gene discussed is CNBP; the disease is myotonic dystrophy type 1.