KCNH2 and familial long QT syndrome: Multiple genes have been found to cause LQTS and these include KCNQ1 (LQT1), KCNH2 (LQT2), SCN5A (LQT3), ANK2 (LQT4), KCNE1 (LQT5), KCNE2 (LQT6), KCNJ2 (LQT7), CACNA1C (LQT8), CAV3 (LQT9) and SCNB4 (LQT10).