Polymorphisms in estrogen receptor-α are associated with idiopathic female infertility

To investigate the relationship between polymorphisms in the estrogen receptor-α (ERα) gene and unexplained female infertility, restriction fragment length polymorphism (RFLP) analysis of ERα was employed in 150 females with idiopathic infertility (study group) and 150 healthy, age-matched females of proven fertility (control group). The results showed that the ERα allele frequencies differed significantly between the study and control groups (P=0.001). The allele identified by PvuII (P) restriction was detected more frequently in the study group (49.0% of individuals) compared to the control group (31.0%; P=0.001), while the allele identified by XbaI (X) restriction was detected less frequently in the study group (19.7%) compared to the control group (35.7%, P=0.001). A similar phenomenon was observed for the distribution of the TA alleles. The TA13 allele was more common in the study group (24.7 vs. 6.7% in controls; P=0.001), while the TA15 allele was less common in the study group (15.3 vs. 27.3% in controls; P=0.034). To conclude, polymorphisms in the ERα gene are associated with idiopathic female infertility. In particular, the P and TA13 alleles may represent significant risk factors, while the X and TA15 alleles may be protective factors.