MYH7 and myotonic dystrophy type 1: In DM1, typically there is type 1 fiber atrophy (MYH7) and type 2 fiber hypertrophy [58,59,60] (Pakleza-Foila Morphol 2011;Vihola-2003), whereas DM2 shows preferential atrophy of type 2 fibers resulting in a relative abundance of type 1 fibers (Figure 9) [58,59,61].