OBJECTIVES: The aim of this study was to screen lone atrial fibrillation (AF) patients for mutations in the genes KCNJ2, KCNJ3 and KCNJ5, all encoding potassium channels. Furthermore, we wanted to replicate the prior association of two single-nucleotide polymorphisms (SNPs) in KCNJ5, C171T (rs6590357) and G810T (rs7118824), with lone AF in Han Chinese.

METHODS: We sequenced the coding region and splice site of KCNJ2, KCNJ3 and KCNJ5 in 187 early-onset lone-AF patients screening for mutations and counting SNP frequencies for the two noted SNPs in KCNJ5.

RESULTS: No mutations were found in KCNJ2, KCNJ3 or KCNJ5. Both genotype distribution and allele frequencies of the SNPs rs6590357 and rs7118824 significantly differed between the AF and control group (p(genotype) = 0.0067, p(allele) = 0.0021 and p(genotype) = 0.014, p(allele) = 0.0101, respectively). On allele level, the OR for lone AF for rs6590357 was 1.77 (95% CI 1.16-2.73, p = 0.009) and for rs7118824 it was 1.71 (95% CI 1.13-2.57, p = 0.01) in a model adjusted for age and gender.

CONCLUSIONS: Our findings indicate that rs6590357 and rs7118824 in KCNJ5 are associated with early-onset lone AF in Caucasians. No mutations were found in the exon or splice site of KCNJ2, KCNJ3 or KCNJ5.