Approximately 75% of patients with LQTS carry mutations in 5 genes: KCNQ1 (LQT1), KCNH2 (LQT2), SCN5A (LQT3), KCNE1 (LQT5), and KCNE2 (LQT6) [14]. The gene discussed is KCNE1; the disease is familial long QT syndrome.