TBX20 and atrial septal defect: For example, in the case of atrial septal defect (ASD) and ventricular septal defect (VSD), candidate genes can be counted: NKX2-5, GATA4, TBX20, MYH6, and TBX5, while the pathogenesis of atrioventricular septal defect (AVSD) involves genes, such as PTPN11, KRAS, SOS1, RAF1, and CRELD1.