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). Here, KCNQ1 is linked to familial long QT syndrome.