KCNJ2 and Familial short QT syndrome: To date, six different genes encoding various cardiac ion channels have been identified in the pathogenesis of SQTS, including the KCNH2 [5], KCNQ1 [6], KCNJ2 [7], CACNA1C [8], CACNB2B [8] and CACNA2D1 genes [9].