A, Syncope or lethal cardiac events in patients with long QT syndrome 1 (LQT1). B, Only lethal cardiac events, including ventricular fibrillation and cardiac arrest, in patients with LQT1. C, Syncope or lethal cardiac events in patients with LQT2. D, Only lethal cardiac events, including ventricular fibrillation and cardiac arrest, in patients with LQT2. E, Syncope or lethal cardiac events in patients with LQT3. F, Only lethal cardiac events, including ventricular fibrillation and cardiac arrest, in patients with LQT3. N/C-term indicates N-terminus or C-terminus variants; nonpore MS, membrane-spanning variants excluding the S5-pore-S6; and S5-pore-S6, variants of pore site and segment 5 (S5) to segment 6 (S6).