The Phenotypic Spectrum of a Mutation Hotspot Responsible for the Short QT Syndrome

Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved..

OBJECTIVES: This study sought to evaluate the phenotypic and functional expression of an apparent hotspot mutation associated with short QT syndrome (SQTS).

BACKGROUND: SQTS is a rare channelopathy associated with a high risk of life-threatening arrhythmias and sudden cardiac death (SCD).

METHODS: Probands diagnosed with SQTS and their family members were evaluated clinically and genetically. KCNH2 wild-type (WT) and mutant genes were transiently expressed in HEK293 cells, and currents were recorded using whole-cell patch clamp and action potential (AP) clamp techniques.

RESULTS: KCNH2-T618I was identified in 18 members of 7 unrelated families (10 men; median age: 24.0 years). All carriers showed 100% penetrance with variable expressivity. Eighteen members in 7 families had SCD. The average QTc intervals of probands and all carriers was 294.1 ± 23.8 ms and 313.2 ± 23.8 ms, respectively. Seven carriers received an implantable cardioverter-defibrillator. Quinidine with adequate plasma levels was effective in prolonging QTc intervals among 5 cases, but 3 cases still had premature ventricular contraction or nonsustained ventricular tachycardia. Bepridil successfully prevented drug-refractory ventricular fibrillation in 1 case with 19-ms prolongation of the QTc interval. Functional studies with KCNE2 revealed a significant increase of IKr (rapidly activating delayed rectifier potassium channel) tail-current density in homozygous (119.0%) and heterozygous (74.6%) expression compared with WT. AP clamp recordings showed IKr was larger, and peak repolarizing current occurred earlier in mutant versus WT channels.

CONCLUSIONS: We reported the clinical characteristics and biophysical properties of the highly frequent mutation that contributes to genetically identified SQTS probands. These findings extend our understanding of the spectrum of KCNH2 channel defects in SQTS.

Errataetall:

CommentIn: JACC Clin Electrophysiol. 2017 Jul;3(7):744-746. - PMID 28966985

Medienart:

E-Artikel

Erscheinungsjahr:

2017

Erschienen:

2017

Enthalten in:

Zur Gesamtaufnahme - volume:3

Enthalten in:

JACC. Clinical electrophysiology - 3(2017), 7 vom: 19. Juli, Seite 727-743

Sprache:

Englisch

Beteiligte Personen:

Hu, Dan [VerfasserIn]
Li, Yang [VerfasserIn]
Zhang, Jiancheng [VerfasserIn]
Pfeiffer, Ryan [VerfasserIn]
Gollob, Michael H [VerfasserIn]
Healey, Jeff [VerfasserIn]
Harrell, Daniel Toshio [VerfasserIn]
Makita, Naomasa [VerfasserIn]
Abe, Haruhiko [VerfasserIn]
Sun, Yaxun [VerfasserIn]
Guo, Jihong [VerfasserIn]
Zhang, Li [VerfasserIn]
Yan, Ganxin [VerfasserIn]
Mah, Douglas [VerfasserIn]
Walsh, Edward P [VerfasserIn]
Leopold, Harris B [VerfasserIn]
Giustetto, Carla [VerfasserIn]
Gaita, Fiorenzo [VerfasserIn]
Zienciuk-Krajka, Agnieszka [VerfasserIn]
Mazzanti, Andrea [VerfasserIn]
Priori, Silvia G [VerfasserIn]
Antzelevitch, Charles [VerfasserIn]
Barajas-Martinez, Hector [VerfasserIn]

Links:

Volltext

Themen:

Channelopathy
ERG1 Potassium Channel
Genetics
Journal Article
KCNH2 protein, human
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Short QT syndrome
Sudden cardiac death
Therapy

Anmerkungen:

Date Completed 09.07.2019

Date Revised 09.07.2019

published: Print-Electronic

CommentIn: JACC Clin Electrophysiol. 2017 Jul;3(7):744-746. - PMID 28966985

Citation Status MEDLINE

doi:

10.1016/j.jacep.2016.11.013

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM284061816