TNNT2 and familial dilated cardiomyopathy: Patient-derived hiPSC-CMs with a TNNT2 R173W mutation were used to recapitulate the DCM phenotype and decreased contractility, reduced Ca2+ transient parameters consistent with reduced SR Ca2+ load, and abnormal α-actinin distribution, which could be corrected with the β-blocker metoprolol (Sun et al., 2012).