NKX2-5 and cardiac conduction defect: Interestingly, although some other transcript factors, such as NKX2-5, have been associated with cardiomyopathy and septal defects and have also been linked with cardiac conduction disorders, we did not find an association of TBX20tv and cardiac conduction disorders, and only one of the patients of the cohort required pacemaker implantation due to sinus node dysfunction.