DMPK and myotonic dystrophy type 2: Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are multisystemic diseases caused by 50-4000 CUG trinucleotide repeat expansions in the 3′ untranslated region (UTR) of the myotonic dystrophy protein kinase (DMPK) gene and 55–11,000 CCUG repeats in the first intron of the cellular nucleic acid-binding protein (CNBP) gene, respectively.