KCNJ2 and Familial short QT syndrome: These rare variants have been identified in five genes: KCNQ1, KCNJ2, CACNA1C, CACNB2, and SCN5A. Therefore, rare variants potentially associated with SQTS or similar phenotypes are reported in eight genes: CACNA1C, CACNA2D1, CACNB2, KCNH2, KCNJ2, KCNQ1, SCN5A, and SLC4A3.