TTN and familial dilated cardiomyopathy: In particular, titin truncating mutations often occur in the A-band (Herman et al. 2012) and are a leading cause of dilated cardiomyopathy (DCM) (Roberts et al. 2015), causing 25% of familial cases of idiopathic dilated cardiomyopathy and 18% of sporadic cases (Herman et al. 2012).