DM1 is caused by an expansion of CTG repeats in the 3′ untranslated region of the DMPK gene (Figure 1) (OMIM *605377) [3,4,5], while DM2 is caused by an expansion of CCTG repeats in the first intron of the CNBP gene (OMIM *116955) [6]. This evidence concerns the gene DMPK and myotonic dystrophy type 1.