The non-synonymous coding IKr-channel variant KCNH2-K897T is associated with atrial fibrillation: results from a systematic candidate gene-based analysis of KCNH2 (HERG).
OBJECTIVE
Atrial fibrillation (AF) is the most frequent arrhythmia in humans. Rare familial forms exist. Recent evidence indicates a genetic susceptibility to common forms of AF. The alpha-subunit of the myocardial I(Kr)-channel, encoded by the KCNH2 gene, is crucial to ventricular and atrial repolarization. Patients with mutations in KCNH2 present with higher incidence of AF. Common variants in KCNH2 have been shown to modify ventricular repolarization. We intended to investigate, whether such variants may also modulate atrial repolarization and predispose to AF.


RESULTS
In a two-stage association study we analysed 1207 AF-cases and 2475 controls. In stage I 40 tagSNPs (single nucleotide polymorphisms) from the KCNH2 genomic region were genotyped in 671 AF-cases and 694 controls. Of five associated variants, the common K897-allele of the KCNH2-K897T variant was replicated in n = 536 independent AF cases and n = 1781 controls in stage II [overall odds ratio 1.25, 95% confidence interval 1.11-1.41, P = 0.00033]. This association remained significant after adjustment for gender and age.


CONCLUSIONS
We report a genetic association finding including positive replication between the K897-allele and higher incidence of AF. This provides a molecular correlate for complex genetic predispositions to AF. The consequences of the K897T variant at the atrial level will require further functional investigations.
Sinner
Moritz F
MF
Department of Medicine I, Ludwig-Maximilians-University Munich, Klinikum Grosshadern, Marchioninistr. 15, Munich D-81377, Germany.
Pfeufer
Arne
A
Akyol
Mahmut
M
Beckmann
Britt-Maria
BM
Hinterseer
Martin
M
Wacker
Annette
A
Perz
Siegfried
S
Sauter
Wiebke
W
Illig
Thomas
T
Näbauer
Michael
M
Schmitt
Claus
C
Wichmann
H-Erich
HE
Schömig
Albert
A
Steinbeck
Gerhard
G
Meitinger
Thomas
T
Kääb
Stefan
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006239:Haplotypes / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D015221:Potassium Channels / Q000235:genetics; D018709:Statistics, Nonparametric; D015534:Trans-Activators / Q000235:genetics / Q000302:isolation & purification; D000071230:Transcriptional Regulator ERG
D004268:DNA-Binding Proteins; C072312:ERG protein, human; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D015221:Potassium Channels; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG