RYR2 and catecholaminergic polymorphic ventricular tachycardia: Mutations in RyR1 are associated with various muscle diseases, such as malignant hyperthermia (MH), central core disease (CCD), and multi-minicore disease (MmD) (Robinson et al. 2006; Treves et al. 2008) and those in RyR2 are linked with several arrhythmogenic heart diseases, such as catecholaminergic polymorphic ventricular tachycardia (CPVT) (Priori et al. 2002; Tester et al. 2004; Kawamura et al. 2013).