Background Growing epidemiologic evidence has indicated that genetics can predispose individuals to the occurrence of lone atrial fibrillation (AF).The angiotensin-converting enzyme 2 (ACE2) gene has been established to be associated with hypertension and left ventricular hypertrophy.The objective of our study was to investigate the association of ACE2 gene polymorphisms with lone AF.Methods A total of 265 consecutive lone AF patients and 289 healthy controls were successfully investigated.The polymorphisms rs2106809 and rs2285666 were genotyped by polymerase chain reaction (PCR) and direct sequencing.A Logistic regression model was used to determine the odds ratio (OR) and 95％ confidence intervals (CI) of variations of ACE2 for lone AF.Results The T allele of rs2106809 conferred an increased risk for lone AF (OR 1.24,95％ CI 1.01-1.52,P=0.03) in males after adjustment for conventional risk factors.SNP at rs2285666 in males was not significantly different between AF patients and controls.No association was found between the two polymorphisms in the female population with lone AF.After (36.3±4.5) months of follow-up,the end point data were obtained:death (cardiac and noncardiac),ischemic stroke,and heart failure.In the male subgroup,the associations between rs2106809 T male carriers and combined end points including ischemic stroke,heart failure,and death in our study were of significance (OR 3.6,95％ CI 1.0-13.1,P=0.04).Conclusions The results indicate that polymorphism at ACE2 gene is associated with male lone AF in a Chinese Han population.Lone AF males who carry the rs2106809 T allele are associated with adverse cardiac events.