In total, 5 of the 105 (5%) identified mutations had occurred de novo in the index patient (four LQTS mutations and one CPVT mutation, KCNQ1 p.T169R, KCNH2 p.E95G, KCNH2 p.Q61R, SCN5A p.V411M, and RYR2 p.S2246L, see Table 2). This evidence concerns the gene SCN5A and familial long QT syndrome.