KCNJ2 and familial long QT syndrome: The total prevalence of the KCNJ2 gene mutations in LQTS patients seems to be low all over the world: 0.74% mutation carriers was reported in a large cohort of LQTS patients in the US [20], which was not very different from the Australian LQTS cohort (0.93%) [21] and low prevalence (1%) in this study.