association of the +49 a/g polymorphism of ctla4 gene with idiopathic recurrent spontaneous abortion in women in southwest of iran

background: survival of the semi-allograft fetus during pregnancy opens a new area for the immunological based causes of recurrent spontaneous abortion (rsa). cytotoxic t lymphocyte-associated antigen 4 (ctla4) is a negative regulator of the t-cell activation, which may modulate peripheral self-tolerance of the allogeneic fetus. the present study aimed to investigate the +49 a/g ctla4 genetic polymorphism and predisposition to rsa. methods: the total participants were 120 women with at least two miscarriages and 120 healthy post-menopausal women as the control group. the +49 a/g polymorphism was genotyped using pcr-rflp method. required demographic information was collected through filling out a questionnaire. the obtained data were fed into spss software version 16. results: the results showed a significant association between the minor alleles (g) with the decreased risk of the rsa. the frequency of the g allele in controls and patients was 25% and 12%, respectively. a gg genotype in the co-dominance model (or: 0.25, 95%ci: 0.09-0.66) and in the dominant model for allele g (gg+ag vs. aa) (or: 0.84, 95%ci: 0.8-0.87) showed significant association with rsa by imposing the protective role. the frequency of miscarriage is significantly (p=0.04) higher among the relatives of rsa women (33.3%) in comparison with the women in the control group (21.7%). conclusion: it can be concluded that +49g allele may act as a dominant allele and reduce the risk of rsa. family history of miscarriage increased the risk of rsa among women.