The absence of severe fixed weakness or muscle wasting distinguishes NDMs from dystrophic myotonias, such as myotonic dystrophies type 1 and type 2 (DM1 and DM2 due to DMPK and CNBP mutations, respectively), which present with both progressive muscle weakness and multisystem involvement (Figure 4) (87). This evidence concerns the gene CNBP and myotonic dystrophy type 1.