DMPK and myotonic dystrophy type 1: DM1, also known as Steinert’s disease, is caused by a CTG triplet repeat expansion in the last exon of DMPK gene, encoding the myotonin-protein kinase (MT-PK), which plays an important role in regulating the production and function of muscle structures by interacting with other proteins and in the communication of muscle, heart and brain cells [20].