Mbnl2 KO mice or sequestration of MBNL2 in human DM1 results in mis-splicing of Gabrg2 (Charizanis et al., 2012; Weyn-Vanhentenryck et al., 2018; Otero et al., 2021) in which exon 9 is excluded, producing the short, fetal isoform (Gabrg2S). Here, MBNL2 is linked to myotonic dystrophy type 1.