Shimizu W, et al. - In this study involving 1,124 genotype-positive patients from 11 Japanese institutions from March 1, 2006, to February 28, 2013, researchers investigated the relationship between sex and location of the long QT syndrome (LQTS)-related pathogenic variant as it pertains to the risk of life-threatening arrhythmias. Pathogenic variants in the pore areas of the channels were correlated with higher risk of arrhythmic events than were other variants in each genotype, noted the investigators. On the other hand, sex-related differences were found in patients with LQTS type 1 (LQT1) and type 2 (LQT2) but not in patients with type 3 (LQT3). Overall, the risk for cardiac events in LQTS seem to vary based on genotype, variant site, age, and sex.