KCNH2 and Familial short QT syndrome: 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.