TTN and familial dilated cardiomyopathy: Variants in the most common myofilament DCM genes such as those expressing titin (Vikhorev et al., 2022), troponin T (Reda and Chandra, 2019), or troponin C (Dweck et al., 2008, 2010) directly cause variations in maximal force, passive tension, cross-bridge kinetics, as well as variations (often a reduction) in myofilament Ca2+ sensitivity and length-dependent activation.