In heart failure and cardiomyopathy, RBPMS cooperates with RBM20 to regulate splicing of sarcomeric genes such as TTN, safeguarding contractile integrity [208], while DDX5 maintains calcium homeostasis through CAMK2D splicing [204], and loss of QKI results in profound sarcomere disarray and heart failure [205]. The gene discussed is CAMK2D; the disease is heart failure.