RYR2 and autosomal dominant cerebellar ataxia: RyR2 gain-of-function (GOF) pathogenic variants account for 60% of autosomal dominant type 1 catecholaminergic polymorphic ventricular tachycardia (CPVT1), a potentially lethal, heritable arrhythmia syndrome that classically manifests as exercise-induced syncope, sudden cardiac arrest (SCA), or sudden unexplained death in the young (SUDY) in the setting of a structurally normal heart (2–4).