CALM1 and paroxysmal familial ventricular fibrillation: Nevertheless, to date, several mutations have been identified in human CALM genes (~36 in CALM1, 23 in CALM2 and 15 in CALM3), some of them associated with life-threatening conditions in childhood and mainly arrhythmias, such as catecholaminergic polymorphic ventricular tachycardia, long QT syndrome and idiopathic ventricular fibrillation [64–66].