TTN and familial dilated cardiomyopathy: Indeed, titin has been implicated in a variety of heart muscle diseases among which dilated cardiomyopathy (DCM) and heart failure with preserved ejection fraction (HFpEF)/diabetic cardiomyopathy (DbCM) are the most prominent (Table 1) (Herman et al., 2012; Zile et al., 2015; Hopf et al., 2018).