FKBP1B and catecholaminergic polymorphic ventricular tachycardia: The affinity of calstabin-2 for RyR2 correlates with the degree of structural changes introduced by the mutations (i.e. the primed state) and the age of onset of symptoms of the CPVT patients, suggesting that the affinity of calstabin-2 for RyR2 is a predictive tool of the level of primed state and the pathogenicity of remodeled RyR2.