KCNE1 and familial long QT syndrome: No mutations were identified in KCNQ1 (codes for the α subunit of the slowly-activating IKS channel), KCNE1(codes for the β subunit of the IKS potassium channel), or KCNE2 (codes for the β subunit of the rectifying IKr potasium channel) or other channel-related LQTS genes.