NKX2-5 and congenital heart disease: Although gestational hypoxia and a mutation in Nkx2-5 in mice have been shown to cause congenital heart disease (8, 24, 25), we report for the first time to our knowledge that non-genetic and genetic cardiac anomalies share a common mechanism relating to abnormal function of Nkx2-5, at least at a specific developing stage, E12.5.