NKX2-5 and heart failure: Nkx2-5 regulates multiple downstream targets including cMLCK (Chan et al., 2008), and perinatal Nkx2-5-KO mice demonstrate more profound heart failure compared to perinatal Mylk3-KO mice, with a 1.44 fold increase of HW/BW ratio at P12 (Briggs et al., 2008).