The IL-6 -634C/G polymorphism: a candidate genetic marker for the prediction of idiopathic recurrent pregnancy loss

BACKGROUND Recurrent pregnancy loss (RPL) is defined as two or more miscarriages before the 20(th) week of gestation and its etiology is unknown in 50% of the cases. Interleukin 6 is an immune mediator, plays a regulatory role in embryo implantation and placental development. OBJECTIVE The purpose was to assess the association between IL-6 -634C/G polymorphism and, susceptibility to idiopathic RPL for the first time in Iran. MATERIALS AND METHODS In total 121 women with RPL and 121 healthy women as control group were enrolled in this case-control study. This study was performed from August 2013 to October 2014 in the Molecular Genetics Laboratory of Arsanjan University. Candidate polymorphism was evaluated by PCR-RFLP method on extracted genomic DNA. Data was analyzed using the statistical SPSS package. RESULTS Our results showed an increased risk of RPL in patients with GG + GC genotype (OR=5.1, 95%CI: 1.04-25.3, p=0.04) in comparison to CC genotype. The frequency of mutant allele G in patients and controls was 0.75 and 0.66 respectively. The mutant allele G predisposes women to miscarriage 1.5 times greater than controls (OR=1.5, 95%CI: 1.03-2.27, p=0.036). The mean number of live births in RPL women (1.3±2.3) was significantly lower compared to control women (4.8±2.3). CONCLUSION This study indicated that the promoter polymorphism (-634C/G) of the IL-6 gene has likely influence on individual susceptibility to RPL.