SCN5A and Familial short QT syndrome: Some variants in calcium- and sodium-channel genes have also been detected in patients with SQTS, including CACNA1C-G490R,29CACNA1C-A39V and CACNA1C -R1937P,29,30CACNB2-S481L (29), CACNA2D1-S755T,31 and SCN5A-R689H.25