The disorder encompasses two genetically distinct types: myotonic dystrophy type 1 (DM1, OMIM 160900) and myotonic dystrophy type 2 (DM2, OMIM 602668), attributable to CTG expansion in 3’UTR of the DMPK gene and CCTG repeats in the first intron of the CNBP gene, respectively (Kumar et al, 2013). Here, DMPK is linked to myotonic dystrophy type 1.