Comprehensive mutation scanning of KCNQ1 in 111 Han Chinese patients with lone atrial fibrillation

To determine the extent to which genetic variation in the potassium channel gene KCNQ1 causes atrial fibrillation (AF).

Case-control study.

National University Hospital, Singapore.

Han Chinese patients (n=111) with lone AF (onset <60 years and lacking risk factors) and 265 Han Chinese controls.

Blood draw, 12-lead electrocardiogram and transthoracic echocardiogram were performed on patients with AF at enrolment.

DNA sequence variants in the coding region and exon-intron boundaries of KCNQ1 as detected by direct sequencing.

Four previously reported coding variants were identified: I145I, S546S, P448R and G643S. An additional 19 non-coding variants were identified, nine of which are newly reported. None were predicted to create a cryptic splicing site. The allele frequencies of the two non-synonymous variants did not differ significantly in the AF cases compared with 265 Han Chinese controls (P448R: 10.8% in cases vs 8.6% in controls, p=0.41; G643S: 1.4% in cases vs 0.8% in controls, p=0.43).

Comprehensive mutation scanning of KCNQ1 did not identify novel pathogenic mutations or risk-conferring polymorphisms. As in Caucasians, genetic variation in KCNQ1 is not a common cause of AF in Han Chinese. Routine genetic testing of KCNQ1 for AF is, therefore, not warranted.