TBX20 and mitral valve stenosis: In 2007, Kirk and coworkers [63] first reported two missense mutations and one nonsense mutation in TBX20 identified in patients suffering from diverse cardiac pathologies, encompassing defects of septation (atrial/ventricular septal defect) and valvular malformation (mitral valve stenosis and prolapse), aortic coarctation, and cardiomyopathy [63].