In humans, disease causing mutations in the homeodomain protein NKX2-5 result in a plethora of CHDs including ASD, VSD, TOF and DORV [69–71] Septal defects and atrio-ventricular conduction defects are commonly seen in patients with a mutated NKX2-5 gene [70]. This evidence concerns the gene NKX2-5 and atrial septal defect.