GJA1 and atrial fibrillation: In left atrial samples, eQTL analyses revealed that the AF risk allele, SNP rs13216675, downregulated the expression of the gene GJA1, while the SNP rs10507248 upregulated the expression of the gene TBX5. There were also other genes related to AF in European Caucasians among the 49 SNPs initially analyzed; however, their association with AF was limited even though they met the significance threshold.