To address why these 2 diseases present disparate muscle phenotypes despite shared sequestration of MBNL proteins, we determined the expression of DMPK, CNBP, and MBNL1 genes across healthy human muscles using a transcriptomic atlas, and we evaluated multiple muscles from Mbnl-KO mice to assess differential susceptibility, which muscles better recapitulate DM pathology, and whether mouse muscles resemble DM1, DM2, or neither following MBNL loss. Here, DMPK is linked to myotonic dystrophy type 1.