RYR2 and hereditary disease: CPVT comprises heterogeneous genetic diseases, including mutations in ryanodine receptor type 2 (RyR2), calsequestrin 2 (CASQ2), triadin, or calmodulin (Leenhardt et al, 1995; Lahat et al, 2001; Priori et al, 2002; Chopra & Knollmann, 2011; Nof et al, 2011; Arad et al, 2012; Hwang et al, 2014).