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]. The gene discussed is NKX2-5; the disease is atrioventricular block.