Therefore, the most recent evidence in diagnostic procedure suggested analysing KCNQ1, KCNH2, SCN5A genes only; CACNA1C, CALM1, CALM2, CALM3, KCNE1, KCNE2, KCNJ2, TRDN genes should be included in syndromic LQTS, or LQTS with atypical features, or in acquired LQTS (i.e., drug- or electrolyte-provoked LQTS) [57]. This evidence concerns the gene TRDN and familial long QT syndrome.