KCNJ2 and catecholaminergic polymorphic ventricular tachycardia: Majority of CPVT cases arise from mutations in the gene coding for cardiac ryanodine receptor, RYR2. Other genes are also implicated in CPVT, but in far lesser extent, for example, ANK2, CALM1, CALM2, CASQ2, KCNJ2, SCN5A, TECRL, and TRDN [2].