KCNH2 and Bradycardia: It was shown that de novo compared to familial LQTS can present with a more severe prenatal phenotype [8] and that different forms of bradycardia are associated with specific disease genes: sinus bradycardia seemed to be associated with KCNQ1, while bradycardia caused by artrioventricular (AV) block was caused by variants in KCNH2 in neonates in a previous study [9].