While our review focuses on gene–disease associations in SQTS, we acknowledge that variant classification follows the ACMG 5-tier system [145], with several mutations in KCNH2, KCNQ1, KCNJ2, and SLC4A3 being classified as pathogenic or likely pathogenic in databases such as ClinVar and ClinGen. Here, KCNJ2 is linked to Familial short QT syndrome.