INSR and myotonic dystrophy type 1: In skeletal muscles of patients with Type 1 Myotonic Dystrophy (DM1), the splicing pattern of the insulin receptor (INSR) gene undergoes a pathological shift, resulting in a significant increase in the expression of the IR-A isoform, which has lower metabolic signaling capability, while the IR-B isoform is reduced (37–39).