TTN and familial dilated cardiomyopathy: Together, these observations demonstrate that TTNtv protein was present in myocardium from a TTNtv-bearing DCM patient; that the TTNtv protein was incorporated into the sarcomere akin to full-length titin, binding both the Z-disk and the thick filament; and that this A-band overlapping truncated titin bore force across the I-band, even under supraphysiological strain, but detached more readily from the thick filament compared with full-length titin (Figure 1F).