Aberrant splicing and expression of the non muscle myosin heavy-chain gene MYH14 in DM1 muscle tissues

► A splicing unbalance of the MYH14 gene has been reported in DM1 muscles. ► DM1 patients over-express a MYH14 isoform encoding for a protein with lower activity. ► MYH14 mRNA and protein levels are reduced in DM1 muscles compared to controls. ► The subcellular localization of the NMHC II-C protein is not altered in DM1 muscles. ► Levels of MBNL1 protein regulate the splicing of MYH14 transcript.