Another variant, i.e., CPVT3, was found with the mutations in the TRDN gene, where 97 probands (index cases found to have phenotypical CPVT) were screened and three related variants were found, which encode for a protein that links RyR2 and CASQ2 in the sarcoplasmic reticulum (SR). The gene discussed is TRDN; the disease is catecholaminergic polymorphic ventricular tachycardia.