RYR2 and catecholaminergic polymorphic ventricular tachycardia: CPVT comprises two subtypes; CPVT1 arises from mutations in the cardiac ryanodine receptor 2 (RYR2), and CPVT2 is caused by a mutation in the calsquestrin-2 (CASQ2) gene (Leenhardt et al., 2012; Roston et al., 2017).