Familial aggregation of atrial fibrillation: a study in Danish twins

Evaluation of non-synonymous NPPA single nucleotide polymorphisms in atrial fibrillation

AIMS

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is an important cause of morbidity and mortality. A genetic mutation in the NPPA gene, which encodes the atrial natriuretic peptide, has been identified as the putative causative factor in a family with an autosomal dominant pattern of inheritance for AF. Two common single nucleotide polymorphisms (SNPs) in NPPA, rs5063 and rs5065, result in amino acid changes of the primary peptide and have been previously implicated in conditions associated with AF, including stroke and hypertension. Recently, the rs5063 SNP has been reported to confer an increased risk of AF development in a Chinese population. We sought to examine the associations of both rs5063 and rs5065 with AF in two separate North American cohorts of European ancestry.

METHODS AND RESULTS

Patients with early-onset AF, along with healthy controls, were recruited at the University of Ottawa Heart Institute (UOHI) and the Massachusetts General Hospital (MGH). Study participants were genotyped for rs5063 and rs5065 using a combination of restriction fragment length polymorphism analysis and DNA microarrays. The study genotyped a total of 620 AF cases and 2446 healthy controls. The UOHI arm of the study identified an odds ratio (OR) of 0.72 [95% confidence interval (CI): 0.42-1.24] for rs5063, whereas an OR of 1.33 (95% CI: 0.80-2.21) was observed in the MGH arm. The combined OR approximated unity (OR 0.99; 95% CI: 0.54-1.80). Analysis of rs5065 revealed an OR of 1.12 (95% CI: 0.84-1.48) in UOHI, 1.08 (95% CI 0.80-1.45) in MGH, and 1.10 (95% CI 0.90-1.35) when combined.

CONCLUSION

Common non-synonymous genetic variants within NPPA in these two large North American cohorts of European ancestry are not associated with the development of AF.

Familial aggregation of lone atrial fibrillation in the Chinese population

OBJECTIVE

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia associated with substantial morbidity and significant mortality. The familial aggregation of AF elsewhere in the world has been documented. This investigation sought to evaluate familial aggregation of lone AF in the Chinese population.

METHODS

The study population included 382 unrelated patients with lone AF, and their 6,856 relatives. The controls were 15,507 age-sex-matched individuals from the general population. The prevalence of AF in each class of relatives was compared to that in each subgroup of the age- and sex- comparable control individuals.

RESULTS

The relatives of patients with lone AF had a significantly increased risk of the arrhythmia as compared to the general population. The relative risk (95% confidence intervals) of AF for relatives compared to the general population was: 37.36 (12.71-109.9) for sons, 166.6 (22.06-1258) for daughters, 27.39 (14.63-51.26) for brothers, 24.49 (14.01-42.83) for sisters, 4.87 (2.84-8.35) for mothers, and 4.78 (3.00-7.59) for fathers.

CONCLUSION

These findings provide evidence suggesting that there is a significant familial aggregation of lone AF among Chinese families and a Mendelian genetic component involved in the pathogenesis of this prevalent disorder.