RBM20 and familial dilated cardiomyopathy: RBM20 mutations lead to a severe form of DCM with high rates of heart failure, arrhythmias, and sudden cardiac death (Brauch et al. 2009; Li et al. 2010; Wells et al. 2013; van den Hoogenhof et al. 2018), a complex phenotype resulting from missplicing of several RBM20 target genes (Guo et al. 2012; Maatz et al. 2014).