RYR2 and catecholaminergic polymorphic ventricular tachycardia: Presently, more than 150 mutations have been identified in the RyR2 gene,14 preferentially located in four highly conserved regions (domains I–IV) of the gene.15 The second variant is an autosomal recessive form caused by mutations in the cardiac specific isoform of the calsequestrin gene CASQ2 (CPVT2) which represents only 3%–5% of CPVT patients.4 To date, 15 CASQ2 mutations have been identified in the short arm of chromosome 1 which lead to severe decrease or complete loss of the CASQ2 protein.4