MIB1 and left ventricular noncompaction: NRG1 gain-of-function (R26Nrg1GOF; Nkx2.5Cre) causes premature VCS differentiation [19], while the loss of MIB1-NOTCH signaling (Mib1flox; Tnnt2Cre) results in left ventricular non-compaction cardiomyopathy (LVNC), marked by excessive trabeculation, impaired ventricular wall maturation, and cardiac dysfunction [9,20].