Moreover, there are three atypical LQTS or multisystem syndromic disorders including Ankyrin-B syndrome gene ANK2 (LQT4), Anderson–Tawil syndrome (ATS) gene KCNJ2 (LQT7), and Timothy syndrome (TS) gene CACNA1C (LQT8) [42]. Here, KCNJ2 is linked to familial long QT syndrome.