Association of genetic variants with atrial fibrillation

Update about atrial fibrillation genetics

PURPOSE OF REVIEW

Atrial fibrillation is an important cause of morbidity in the aging population. The mechanisms responsible for the triggering and maintenance of the chaotic atrial rhythm are still poorly understood. In this review, we will focus on the genetic aspects of atrial fibrillation, to understand causality, with special emphasis on recent studies published in the field.

RECENT FINDINGS

Diseases such as hypertension, valvular heart disease, and heart failure may induce atrial fibrillation, which increases the risk of stroke and sudden cardiac death. Clinical studies published in these last two decades have provided evidence that genetics play a key role in atrial fibrillation. Thus, a family history of the disease has been identified in up to 30% of clinically diagnosed patients. In those genotyped families, most carry rare genetic variants in genes associated with ionic channels, calcium handling protein, or predisposing to fibrosis, conduction system disease, and inflammatory processes.

SUMMARY

Currently, atrial fibrillation is the most common sustained arrhythmia in clinical practice. The pathophysiological mechanisms of atrial fibrillation are complex. A better understanding of the molecular basis will help improve both current risk stratification and clinical management.

Effect of Interleukin-27 Genetic Variants on Atrial Fibrillation Susceptibility

AIM

Atrial fibrillation (AF) is the most common cardiac arrhythmia. No data are available on the association between the polymorphisms of interleukin-27 (IL-27) and AF in the Chinese Han population. This study was performed to determine if polymorphisms within the IL-27 gene are involved in the AF susceptibility.

METHODS

Two hundred seventy AF patients and 303 healthy individuals were examined for two IL-27 gene polymorphisms (rs153109 and rs17855750) by polymerase chain reaction-restriction fragment length polymorphism methodology.

RESULTS

An association between the IL-27 single nucleotide polymorphism (SNP) rs153109 and AF was found in Chinese Han population. The G allele and GG genotype of rs153109 were associated with increased AF risk (odds ratio [OR]: 1.35, 95% confidence intervals [CI] = 1.06-1.71, p = 0.02 and OR: 1.66, 95% CI = 1.03-2.65, p = 0.03 in the recessive genetic model, respectively). The significance of the association between the GG genotype and AF risk did not survive a Bonferroni's correction. Similarly, no significant differences in the allele and genotype frequencies of the rs17855750 SNP was observed between the AF patients and controls.

CONCLUSIONS

Our findings indicated that the IL-27 genetic polymorphisms may be associated with susceptibility of AF in Chinese Han population.

The Coronary Artery Disease-associated Coding Variant in Zinc Finger C3HC-type Containing 1 (ZC3HC1) Affects Cell Cycle Regulation

Genome-wide association studies have to date identified multiple coronary artery disease (CAD)-associated loci; however, for most of these loci the mechanism by which they affect CAD risk is unclear. The CAD-associated locus 7q32.2 is unusual in that the lead variant, rs11556924, is not in strong linkage disequilibrium with any other variant and introduces a coding change in ZC3HC1, which encodes NIPA. In this study, we show that rs11556924 polymorphism is associated with lower regulatory phosphorylation of NIPA in the risk variant, resulting in NIPA with higher activity. Using a genome-editing approach we show that this causes an effective decrease in cyclin-B1 stability in the nucleus, thereby slowing its nuclear accumulation. By perturbing the rate of nuclear cyclin-B1 accumulation, rs11556924 alters the regulation of mitotic progression resulting in an extended mitosis. This study shows that the CAD-associated coding polymorphism in ZC3HC1 alters the dynamics of cell-cycle regulation by NIPA.