KCNJ2 and Familial short QT syndrome: A gain-of-function KCNJ2 mutation has been identified in SQTS variant 3 (SQT3), with a 5-year-old child and her father exhibiting a corrected QT interval (QTc) of 315 and 320 ms, respectively, and a narrow and peaked T-wave morphology on the clinical electrocardiogram (ECG) [2].