Patients with CPVT carry mutations in RyR that increase the open probability of the receptor, or in calsequestrin (Casq2) where SR Ca2+ buffering is hindered and/or the interaction of Casq2 and RyR is altered (Cerrone et al., 2009). The gene discussed is CASQ2; the disease is catecholaminergic polymorphic ventricular tachycardia.