Myotonic dystrophy type 1 (DM1), the most common muscular dystrophy in adults and children, is caused by a (CTG)n expansion within the 3′ untranslated region (3′UTR) of the dystrophia myotonica protein kinase (DMPK) gene [1,2]. This evidence concerns the gene DMPK and myotonic dystrophy type 1.