Instead, extended (CTG)n repeats in the 3′-UTR of DMPK gene (DM1) or (CCTG)n repeats in the intron 1 of CNBP gene (DM2) generate pathological effects through RNA toxicity, such as stabilizing CELF1 protein and generation of repeat-associated non-ATG (RAN) proteins (Ranum and Day, 2004; Thornton, 2014; Gourdon and Meola, 2017). Here, DMPK is linked to myotonic dystrophy type 1.