KCNQ1 and familial long QT syndrome: Importantly, in multivariable analyses, carriers of rare, potentially LQTS‐associated variants in KCNQ1 (average 30.0 ms [22.2–37.8]; P=6.0×10−14) or KCNH2 (average 55.5 ms [39.2–71.9]; P=4.0×10−11) had an increase in their QTc compared with noncarriers, whereas the observed QTc difference was not significant in those with rare, potentially LQTS‐associated SCN5A variants (average 9.2 ms [−1.0 to 19.4]; P=0.08), indicating that the value of PRS varies by underlying genotype.16