DM1 is caused by an expanded CTG repeat in the 3′ untranslated region (UTR) of the Dystrophia Myotonic Protein Kinase gene (DMPK) (2–4), while DM2 is caused by expanded CCTG repeats in intron 1 of the CCHC-type zinc finger, Nucleic acid Binding Protein gene (CNBP/ZNF9) (5). Here, CNBP is linked to myotonic dystrophy type 1.