RYR2 and catecholaminergic polymorphic ventricular tachycardia: Although several LQTS-related variants on RYR2 have been reported [18, 60, 61], a considerable part of RYR2 variants are shared with other cardiac diseases, and it is particularly considered as a causative gene for catecholaminergic polymorphic ventricular tachycardia (CPVT).