DM1 results from CTG repeat expansions in the 3′-untranslated region (3′UTR) of the DMPK (dystrophia myotonica protein kinase) gene on chromosome 19 [6,7] while DM2 is caused by CCTG repeat expansions in intron 1 of the CNBP (cellular nucleic acid-binding protein), previously known as ZNF9 (zinc finger protein 9), on chromosome 3 [8,9]. The gene discussed is CNBP; the disease is myotonic dystrophy type 1.