One of the limitations of the approach used in the present study is that cardiac α-MHC controlled K51R expression was restricted to myocardium, therefore the anomalies involving great vessels such as double outlet right ventricle (DORV) and Tetralogy of Fallot (TOF) that were seen in human patients associated with heterozygous Nkx2.5 mutants were not expected/observed in our model. Here, NKX2-5 is linked to Tetralogy of Fallot.