HEY2 and familial atrial fibrillation: Among these gene pairs, NKX2-6 is known to play a key role in cardiac development, and its mutation has been linked to familial atrial fibrillation [41,42]; KCNJ3 is a causative gene of hereditary bradyarrhythmias [43]; MYL2 has been reported to be connected to hypertrophic cardiomyopathy [44,45]; and HEY2 participates in left ventricular maturation [46].