NKX2-5 and atrial septal defect: Furthermore, NKX2-5 plays a critical role in cardiac morphogenesisby regulating transcription of various genes involved in this process [47].Clinically, NKX2-5 haploinsufficiency is associated with progressiveheart defects, such as atrioventricular block, atrial septal defect, andventricular septal defect [48].