KCNQ1 and long QT syndrome 1: There is information that regardless of the KCNQ1 phenotype, that 15% of patients who have missense mutations in the transmembrane C-loop domain have a survival benefit from β-blockers.19 It is known that LQT1 patients with a KCNQ1 missense mutation with a greater degree of loss of function have a greater risk of LQT1-triggered events than LQT1 patients with a C-terminal mutation.