Background Men and women with type-2 long QT syndrome (LQT2) exhibit time-dependent differences in the risk for cardiac events. We hypothesized that data regarding the location of the disease-causing mutation in the KCNH2 channel may affect gender-specific risk in LQT2 Objectives To risk stratify LQT2 patients for life-threatening cardiac events based on clinical and genetic information. Methods The risk for life-threatening cardiac events from birth through age 40 (comprising aborted cardiac arrest [ACA] or sudden cardiac death [SCD]) years was assessed among 1,166 LQT2 males (n=490) and females (n=676) by the location of the LQTS-causing mutation in the KCNH2 channel (pre-specified in the primary analysis as pore-loop vs. nonpore-loop). Results During follow-up, the cumulative probability of life-threatening cardiac events years was significantly higher among LQT2 women (26%) as compared with men (14%; p<0.001). Multivariate analysis showed that the risk for life-threatening cardiac events was not significantly different between women with and without pore-loop mutations (HR=1.20; p=0.33). In contrast, men with pore-loop mutations displayed a significant >2-fold higher risk of a first ACA or SCD as compared with those with nonpore-loop mutations (HR=2.18; p=0.01). Consistently, women experienced a high rate of life-threatening events regardless of mutation-location (pore-loop: 35%, nonpore-loop: 23%), whereas in men the rate of ACA or SCD was high among those with pore-loop mutations (28%) and relatively low among those with nonpore-loop mutations (8%). Conclusion Combined assessment of clinical and mutation-specific data can be used for improved risk stratification for life-threatening cardiac events in type-2 long QT syndrome.