Molecular mechanism of autosomal recessive long QT-syndrome 1 without deafness

  • KCNQ1 encodes the voltage-gated potassium (Kv) channel KCNQ1, also known as KvLQT1 or Kv7.1. Together with its ß-subunit KCNE1, also denoted as minK, this channel generates the slowly activating cardiac delayed rectifier current IKs, which is a key regulator of the heart rate dependent adaptation of the cardiac action potential duration (APD). Loss-of-function mutations in KCNQ1 cause congenital long QT1 (LQT1) syndrome, characterized by a delayed cardiac repolarization and a prolonged QT interval in the surface electrocardiogram. Autosomal dominant loss-of-function mutations in KCNQ1 result in long QT syndrome, called Romano–Ward Syndrome (RWS), while autosomal recessive mutations lead to Jervell and Lange-Nielsen syndrome (JLNS), associated with deafness. Here, we identified a homozygous KCNQ1 mutation, c.1892_1893insC (p.P631fs*20), in a patient with an isolated LQT syndrome (LQTS) without hearing loss. Nevertheless, the inheritance trait is autosomal recessive, with heterozygous family members being asymptomatic. The results of the electrophysiological characterization of the mutant, using voltage-clamp recordings in Xenopus laevis oocytes, are in agreement with an autosomal recessive disorder, since the IKs reduction was only observed in homomeric mutants, but not in heteromeric IKs channel complexes containing wild-type channel subunits. We found that KCNE1 rescues the KCNQ1 loss-of-function in mutant IKs channel complexes when they contain wild-type KCNQ1 subunits, as found in the heterozygous state. Action potential modellings confirmed that the recessive c.1892_1893insC LQT1 mutation only affects the APD of homozygous mutation carriers. Thus, our study provides the molecular mechanism for an atypical autosomal recessive LQT trait that lacks hearing impairment.
Author:Annemarie Oertli, Susanne Rinné, Robin Moss, Stefan KääbORCiD, Gunnar Seemann, Britt-Maria BeckmannORCiDGND, Niels Decher
Parent Title (English):International journal of molecular sciences
Publisher:Molecular Diversity Preservation International
Place of publication:Basel
Document Type:Article
Date of Publication (online):2021/01/23
Date of first Publication:2021/01/23
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/04/14
Tag:KCNQ1; LQTS; electrophysiology; potassium channel
Issue:art. 1112
Page Number:13
First Page:1
Last Page:13
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0