Indeed, CaM mutations have been associated with a spectrum of arrhythmic phenotypes, including LQTS, CPVT, IVF, as well as LQTS/CPVT overlap and Sudden Unexplained Death (SUD) (6, 7, 9, 10, 35–43). This evidence concerns the gene CALM1 and catecholaminergic polymorphic ventricular tachycardia.