Roberts JD, Asaki SY, Mazzanti A, et al. - Via an international multicenter collaboration, researchers intended to better understand the clinical phenotype as well as genetic features related to rare KCNE1 variants involved in type 5 long QT syndrome (LQT5). Exploring 22 genetic arrhythmia clinics and 4 registries from 9 countries, they identified as well as enrolled patients with either presumed autosomal dominant LQT5 (N = 229) or the recessive Type 2 Jervell and Lange-Nielsen syndrome (N = 19). They detected 32 different KCNE1 rare variants in 89 probands and 140 genotype positive family members with presumed LQT5 as well as an additional 19 Type 2 Jervell and Lange-Nielsen syndrome patients. According to the findings, an inclination to QT prolongation was conferred by putative/confirmed loss-of-function KCNE1 variants, however, the low ECG penetrance noted in this study indicates that they do not evident clinically in most of the people, aligning with the mild phenotype seen for Type 2 Jervell and Lange-Nielsen syndrome patients.