KCNQ1 and familial long QT syndrome: Daumy et al. (2016) identified two new mutations by applying targeted next-generation sequencing in 95 unrelated patients with PCCD. Finally, Hof et al. (2017) found four patients with TRPM4 mutations in a cohort of 178 LQTS patients, with no mutations in the three major LQTS genes (KCNQ1, KCNH2, and SCN5A).