RYR2 and sudden cardiac arrest: In addition, VA reported in patients with KCNJ2 mutations have been described as milder than in RYR2 mutated patient, especially rarely leading to syncope or sudden cardiac arrest (Andelfinger et al., 2002; Tristani-Firouzi et al., 2002; Delannoy et al., 2013; Kukla et al., 2014; Inoue et al., 2018).