RYR2 and catecholaminergic polymorphic ventricular tachycardia: RyRs can be classified into three isoforms: RyR1 is predominantly found in skeletal muscle, where specific mutations in its transmembrane region can cause malignant hyperthermia (MH) and central core disease (CCD); RyR2 is abundant in cardiac muscle cells, and mutations in its amino-terminal, carboxy-terminal, and central domains are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT); while RyR3 is less abundant and was originally isolated in the brain [55,56,57].