RYR2 and catecholaminergic polymorphic ventricular tachycardia 1: In this regard, allele-specific downregulation of RYR2- and KCNH2-encoded mutant alleles that cause catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) and LQT2, respectively, successfully decreased the occurrence of arrhythmic events in mice and human-induced pluripotent stem-cell-derived cardiomyocytes (hiPSC-CMs) [17,19].