Genetic variations in the interleukin-21 gene and the risk of recurrent idiopathic spontaneous miscarriage.

OBJECTIVES Insofar as recurrent spontaneous miscarriage (RSM) is linked with dysregulated immunity and inflammatory changes, and given the pro-inflammatory role of interleukin-21 (IL-21), we examined the association between IL-21 polymorphisms and RSM. METHODS AND RESULTS IL-21 rs2055979, rs13143866, rs9992580, and rs4833837 were genotyped in 235 cases of RSM and 235 controls. Regression analysis was employed in assessing the contribution of IL-21 variants to the overall RSM risk. Higher minor allele and genotype frequencies of rs2055979 and rs13143866, but not rs9992580 or rs4833837, were seen in RSM patients than in the controls. IL-21 haplotype [rs9992580/rs4833837/rs2055979/rs13143866] analysis revealed a lower frequency of the TGCG haplotype, and a higher frequency of the GGCG and GAAA haplotypes in patients, thus conferring protection from or a susceptibility to RSM by these haplotypes respectively. Regression analysis confirmed the association of TGCG [OR (95%CI)=0.09 (0.05-0.16)], and GGCG [OR (95%CI)=2.52 (1.34-4.54)] and GAAA [OR (95%CI)=4.02 (2.20-7.70)] haplotypes, after adjusting for age and BMI. CONCLUSIONS Our findings indicate that IL-21 is a novel susceptibility gene for RSM.