LQTS is associated primarily with three genes: KCNQ1 (encoding the α subunit of the IKs-conducting K+ channel), KCNH2 (encoding the α subunit of the IKr-conducting K+ channel), and SCN5A (encoding the α subunit of the INa-conducting Na+ channel) (Wilde et al, 2022). Here, SCN5A is linked to familial long QT syndrome.