GATA4 G295S transgenic mice generated by Misra et al presented with a normal abdominal cardiac morphology and cyclization pattern, but a weak ventricular myocardium and a single ventricle in homozygous mice, which died at the gestational age of 11.5 days; however, the heterozygous line propagated and one subset carried the phenotypes of semilunar valve stenosis and ASD (15). The gene discussed is GATA4; the disease is atrial septal defect.