CASQ2 and catecholaminergic polymorphic ventricular tachycardia: Mutations in genes encoding the RyR2 channel itself [8], or in genes encoding the RyR2 binding proteins cardiac calsequestrin (Casq2) [9], triadin [10, 11] and calmodulin [12] that regulate RyR2 channel open probability have all been associated with a rare inherited arrhythmia syndrome known as catecholaminergic polymorphic ventricular tachycardia (CPVT).