RYR2 and familial long QT syndrome: Of these patients, 15/26 (58%) had an identified genetic mutation with KCNQ1 in 2 and KCNH2 in 4 for LQTS, RYR2 in 4 and CASQ1 in 1 for CPVT, and SCN5A in 3 and ANK2 in 1 for BS.