When SOX4 and Trp97* were co-transfected (simulating the pathological condition of an AF patient with a heterozygous SOX4 mutation of Trp97*), the induced transcriptional activity on the GJA1 promoter was ~6-fold (SOX4 versus Trp97* + SOX4: t = 5.1208; p = 0.0069). This evidence concerns the gene SOX4 and atrial fibrillation.