Genetic aspects associated with increased risk of developing atrial fibrillation

Abstract

Abstract Atrial Fibrillation (AF) is the most common sustained arrhythmia in clinical practice with increasing prevalence and association with increased morbidity and mortality. Studies have suggested a greater contribution of the genetic factor to the etiopathogenesis of arrhythmia, which could indicate up to 40% more risk for the individual who has a family member with the arrhythmia, and later in the form of single nucleotide polymorphisms (SNPs). Objective To verify the association of polymorphisms in the PITX2, HCN4, CAV1 and KCNN3 genes with the occurrence of AF. Method The study is cross-sectional with group comparison, prospective with a quantitative approach. 505 randomly selected subjects were included (357 cases and 148 controls). The real-time PCR methodology was used, using the TAQMAN® system (Thermo scientific, CA, USA). Result The sample was matched by sex and age. The most common type of AF was permanent (69%) followed by paroxysmal (23%). When comparing the groups selected for CAV1, statistical significance was found for AA vs AG genotypes (p 0.003; OR= 2.2; CI 1.29-3.7). For the HCN4 gene allele and genotypes A vs G (p 0.024; OR= 0.66; CI 0.47-0.9) and AA vs AG (p 0.014, OR= 0.57; CI 0.37-0.88), respectively. Regarding the comparison of the dominant and recessive genetic model of each gene, the following models/genes presented statistical significance: in the genotypic model of the CAV1 gene (AA vs AG vs GG) p 0.013, as well as the same model applied to the HCN4 gene (AA vs AG vs GG) (p 0.03); when comparing the dominant models, the HCN4 gene (AA vs AG/GG) presented (p 0.01; OR=0.58; 95% CI 0.38 – 0.88), with the recessive model of the CAV1 gene (AA vs AG/GG) with (p 0.008; OR=2.0; 95% CI: 1.19 – 3.34). Regarding allelic associations between the two groups, a greater chance of susceptibility to developing AF was observed in patients who had the "G" allele (25.6%; p 0.024; OR= 0.66, CI 0.47-0.9) in the HCN4 gene polymorphism. Polymorphisms in the CAV1 (rs3807989) and HCN4 (rs7164883) genes were also included in the multivariate analysis with maintenance of the risk factor for AF. However, only HCN4 rs7164883 showed statistical significan, thus showing it to be an independent variable regarding the probability of the patient with this polymorphism presenting AF. The present study showed a significant association with a greater chance of susceptibility to developing atrial fibrillation in patients with a polymorphism in the CAV1 gene (rs3807989) in a univariate and multivariate model and for patients with the HCN4 gene SNP (rs7164883). Conclusion Therefore, the results revealed an association between the HCN4 gene polymorphism rs7164883 and susceptibility to the development of AF, suggesting that the presence of the G allele may be one of the genetic factors related to the arrhythmia. The CAV1 rs3807989 gene polymorphism also seemed to suggest a risk for the development of AF, also relating the G allele.