CASQ2 and catecholaminergic polymorphic ventricular tachycardia: Because CPVT is related to diastolic [Ca2+]i-overload, and since CASQ2 and RyR2 participate in different aspects of the E-C coupling, we hypothesized that mutations in these genes might be associated with distinct disturbances in the intracellular Ca2+ handing machinery.