KCNJ2 and catecholaminergic polymorphic ventricular tachycardia: KCNJ2-mutated patients with CPVT are all females (Andelfinger et al., 2002; Tester et al., 2006; Kukla et al., 2014), for whom the age of onset or diagnosis ranges from 2 to 36, with a mean around 15, as compared to 8 years old for RYR2-related CPVT (Ackerman et al., 2011).