SYNE2 and atrial fibrillation: We also found that the SNP (rs2738413) with the highest PPA for atrial fibrillation and the cardiac muscle- eQTL in the intron of SYNE2 (Figs. 2g, 5b–d) had been previously identified as an index variant2,4, but proposed to affect expression of the estrogen receptor ESR24, which is located downstream of SYNE2, as 17β-estradiol has arrhythmogenic effects on cardiomyocytes68.