KCNE1

KCNE1, also known as minK, is the gene that encodes the potassium voltage-gated channel subfamily E member 1, a small single-pass transmembrane protein of about 129 amino acids. It functions as an auxiliary subunit that coassembles with voltage-gated potassium channel alpha subunits, most notably KCNQ1 (Kv7.1), to form the slow delayed rectifier potassium current IKs. KCNE1 modulates the channel’s activation kinetics and voltage dependence, contributing to the timely repolarization of the cardiac action potential and to potassium ion homeostasis in the heart.

KCNE1 is expressed in cardiac tissue and in the inner ear, where it participates in potassium recycling in endolymph, a process essential for normal auditory function. Disruption of KCNE1 function impairs both cardiac repolarization and hearing in model systems and humans.

Genetic variation in KCNE1 is associated with long QT syndrome type 5 (LQT5). The most severe condition, Jervell and Lange-Nielsen syndrome (JLNS), is autosomal recessive and combines congenital sensorineural deafness with prolonged QT intervals due to biallelic KCNE1 mutations. Heterozygous KCNE1 variants can contribute to milder or later-onset LQTS phenotypes in some individuals.

Diagnosis relies on clinical evaluation and genetic testing for KCNE1 variants in patients with suspected LQTS or congenital deafness. Management follows standard LQTS practices, including beta-blocker therapy and avoidance of QT-prolonging drugs, with audiologic and, if needed, cochlear interventions for JLNS.