KCNH2 and long QT syndrome 1: There are multiple subtypes of cLQTS with the three most common subtypes being LQT1, caused by mutations in KCNQ1 (accounts for ~45% of genotyped cases); LQT2, caused by mutations in KCNH2 (otherwise known as the human ether‐a‐go‐go related gene, hERG), which accounts for ~40% of genotyped cases and LQT3, caused by mutations in SCN5A, which accounts for ~10% of genotyped cases.