BEST3 and myotonic dystrophy type 1: Accordingly, we chose 35 cassette exons that showed major changes of alternative splicing in the HSALR and Mbnl3⁄4KO RNAseq datasets, including 23 selected for having large shifts of PSI, and another 12 selected because they were previously shown to exhibit splicing misregulation in DM1 patients (Atp2a1, Best3, Bin1, Clasp1, Clcn1, Kif13a, Mbnl1, Mbnl2, Nfix, Opa1, Ryr1 and Vps39), including several that impact muscle function.