In 2012, Ellinor et al. identified six AF susceptibility loci (PRRX1, CAV1, C9orf3, SYNPO2L, SYNE2, and HCN4) in addition to three previously reported loci (PITX2, ZFHX3, and KCNN3) by a genome-wide association study (GWAS) conducted in individuals of European ancestry. This evidence concerns the gene HCN4 and atrial fibrillation.