RYR2 and catecholaminergic polymorphic ventricular tachycardia: The most common subtype, type 1 of CPVT (CPVT1) is a dominantly inherited disease caused by mutations in the cardiac ryanodine receptor (RyR2) gene.[9,10] The gain-of-function mutations of RyR2 cause increased calcium (Ca2+) sensitivity which can lead to spontaneous Ca2+ release from sarcoplasmic reticulum, generation of afterdepolarizations, and triggered activity.[4,5,11]