KLF15 Loss-of-Function Mutation Underlying Atrial Fibrillation as well as Ventricular Arrhythmias and Cardiomyopathy

Ning Li,Xing-Biao Qiu,Yi-Qing Yang,Chen-Xi Yang,Min Zhang,Ruo-Gu Li,Hong-Yu Shi,Ying-Jia Xu,Yu-Han Guo

doi:10.3390/genes12030408

Ning Li, Xing-Biao Qiu + Show 7 more

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https://doi.org/10.3390/genes12030408

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Abstract

Atrial fibrillation (AF) represents the most common type of clinical cardiac arrhythmia and substantially increases the risks of cerebral stroke, heart failure and death. Accumulating evidence has convincingly demonstrated the strong genetic basis of AF, and an increasing number of pathogenic variations in over 50 genes have been causally linked to AF. Nevertheless, AF is of pronounced genetic heterogeneity, and the genetic determinants underpinning AF in most patients remain obscure. In the current investigation, a Chinese pedigree with AF as well as ventricular arrhythmias and hypertrophic cardiomyopathy was recruited. Whole exome sequencing and bioinformatic analysis of the available family members were conducted, and a novel heterozygous variation in the KLF15 gene (encoding Krüppel-like factor 15, a transcription factor critical for cardiac electrophysiology and structural remodeling), NM_014079.4: c.685A>T; p.(Lys229*), was identified. The variation was verified by Sanger sequencing and segregated with autosomal dominant AF in the family with complete penetrance. The variation was absent from 300 unrelated healthy subjects used as controls. In functional assays using a dual-luciferase assay system, mutant KLF15 showed neither transcriptional activation of the KChIP2 promoter nor transcriptional inhibition of the CTGF promoter, alone or in the presence of TGFB1, a key player in the pathogenesis of arrhythmias and cardiomyopathies. The findings indicate KLF15 as a new causative gene responsible for AF as well as ventricular arrhythmias and hypertrophic cardiomyopathy, and they provide novel insight into the molecular mechanisms underlying cardiac arrhythmias and hypertrophic cardiomyopathy.

Highlights

Accumulating compelling evidence underscores the genetic basis of Atrial fibrillation (AF) [16,17,18]
We identified a four-generation AF family (Figure 1A), with 33 living family members
All affected family members had electrocardiogram-documented AF; while the unaffected family members had neither history of AF nor symptoms of AF, with normal electrocardiograms

Summary

Introduction

AF has become a growing socioeconomic burden [13] Despite this clinical significance, the molecular pathogenesis underpinning AF remains largely obscure. Using genome-wide scans with polymorphic genetic markers in AF families and linkage analysis, Brugada and colleagues [19] mapped the first genetic locus for AF on chromosome 10q22–24, the AF-causing gene has not yet been discovered. By positional candidate gene analysis in a large family with AF, Chen and coworkers [20] located a novel genetic locus for AF on chromosome 11p15.5, and within this chromosomal region identified the first AF-causative gene, Ser140Glymutant KCNQ1. In addition to chromosomal duplications/deletions, pathogenic mutations in over 50 genes have been discovered to cause AF, including those encoding ion channels (pore-forming α and auxiliary β subunits), gap junction channels, myocardial structural proteins, cellular signal molecules and cardiac transcription factors [16,17,18,21,22,23,24,25,26,27,28,29,30,31,32,33]

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