Rbm20 missense mutations identified in human patients with DCM and animal models result in expression of the larger N2BA titin isoform (Brauch et al., 2009; Ihara et al., 2020; Li et al., 2010; Refaat et al., 2012; Schneider et al., 2020), and deletion mutations with loss‐of‐function of RBM20 in animal models also lead to expression of the larger titin isoform and DCM in animal models (Guo et al., 2012; van den Hoogenhof et al., 2018; Khan et al., 2016). The gene discussed is RBM20; the disease is familial dilated cardiomyopathy.