Most mutations that have been linked to CPVT are found in two genes, i.e., ryanodine receptor 2 (RyR2) and calsequestrin 2 (CASQ2), two proteins fundamentally involved in the regulation of intracellular Ca2+ in cardiac myocytes. The gene discussed is CASQ2; the disease is catecholaminergic polymorphic ventricular tachycardia.