SCN5A and familial long QT syndrome: Genetic testing, performed afterwards, did not identify diagnostic channel mutations associated with LQTS, (KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2, KCNJ2), but showed three common  polymorphisms (E1061E, D1819D at the SCN5A gene, and S38G at the KCNE1).