RYR1 and catecholaminergic polymorphic ventricular tachycardia: The underlying mechanism causing CPVT and RyR dysfunction in CSQ mutants could be altered Ca2+ buffering in the SR and susceptibility to luminal Ca2+ changes and/or dysregulation of RyR by the CSQ/junctin/triadin/complex (Bassani & Bassani, 2007; Gyorke & Terentyev, 2008).