CLCN1 and facioscapulohumeral muscular dystrophy: Notably, there are a few genes that are misspliced in DM1, and have been linked to a definitive symptomatic outcome, that are misspliced neither in FSHD nor EDMD, namely CLCN1, ATP2A1/2 and MYOM1, of which the CLCN1 missplicing results in the most unique feature of DM1: myotonia.