As LQTS is an autosomal dominant condition, a subset of 56 KCNQ1 variants (coupled to eGFP) were co-transfected with WT KCNQ1 (coupled to mScarlet), in a CHO cell line stably expressing KCNE1, to investigate possible dominant-negative effect of variants. The gene discussed is KCNQ1; the disease is familial long QT syndrome.