Endothelial nitric oxide synthase gene polymorphisms (−786T>C, 4a4b, 894G>T) and haplotypes in Korean patients with recurrent spontaneous abortion

ObjectiveTo investigate the association of three common polymorphisms (−786T>C, 4a4b, 894G>T) of the endothelial nitric oxide synthase (eNOS) gene with idiopathic recurrent spontaneous abortion (RSA).Study designIn a prospective case–control study, 340 patients with unexplained recurrent spontaneous abortion and 115 controls with at least one live birth and no history of pregnancy loss were enrolled. Polymerase chain reaction and restriction fragment length polymorphism analysis were performed to identify the genotypes.ResultsThe recurrent spontaneous abortion patients exhibited a significantly higher frequency of the eNOS 894GT + TT genotype (Odds ratio (OR), 2.39; 95% confidence interval (CI), 1.25–4.58; p = 0.008) compared to the control group; no significant differences in the −786T>C and 4a4b genotype frequencies were observed. The eNOS 894GT genotype (OR, 1.94; 95% CI, 1.00–3.75; p = 0.056) was marginally different between recurrent spontaneous abortion and control groups. The frequency of the −786T-4b-894T haplotype (p = 0.001) was significantly higher in the idiopathic RSA group than in the control group.ConclusionThe eNOS 894GT + TT genotype and the −786T-4b-894T haplotype are significantly associated with idiopathic recurrent spontaneous abortion in Korean women.