KCNQ1 and familial long QT syndrome: Out of the eight heterozygous LQTS probands, one male individual (13%) was diagnosed after dying suddenly at rest at the age of 38 years, two (25%, one female and one male) experienced sudden syncopes, four (50%, all female) were asymptomatic with QTc prolongation on ECG and one female (13%) was asymptomatic with normal findings on ECG (the KCNQ1 variant was identified as an incidental finding in this individual).