TTN and familial dilated cardiomyopathy: Although truncations are found along the length of TTN in DCM patients, in patients with the most severe forms of DCM, truncations reside within the C-terminal two-thirds of the protein (from amino acid 14,760 onwards, Figure 1A), specifically in the distal I-band and A-band (we will refer to these as C-terminal truncations) (Herman et al., 2012; Roberts et al., 2015).