Vitamin D receptor gene polymorphisms and the effectiveness of assisted reproductive technology

Abstract

Introduction. Vitamin D administration is recommended for women with vitamin D insufficiency, who are planning to undergo assisted reproductive treatment (ART). The action of the active form of vitamin D is mediated through its vitamin D receptor (VDR). The presence of VDR in the cells and tissues of the female reproductive system suggests that vitamin D plays an important role in human reproduction. However, the effect of VDR gene polymorphisms on human reproduction has not been adequately studied.Aim. To assess the effect of VDR gene polymorphisms on the folliculogenesis, embryogenesis and clinical outcomes of assisted reproduction programs.Materials and methods. The cross-sectional study included 300 patients without complications during the assisted reproduction cycle. The number of follicles, oocyte-cumulus complexes, mature and immature oocytes, the presence of oocyte dysmorphisms, number of zygotes, fertilization rate, and the number of obtained blastocysts were evaluated. The determination of three polymorphisms of the VDR gene (FokI – rs2228570, BsmI – rs1544410, TaqI – rs731236) was performed by real-time polymerase chain reaction.Results. The incidence of perivitelline space pathology of oocytes in FokI A/A genotype patients was 5.7%, in A/G genotype patients  – 14.7%, in  G/G genotype patients  – 16.3% (p  =  0.041  when comparing A/A  genotype with A/G + G/G genotypes). Depending on the genotype, the pregnancy rate ranged from 38.5 to 52.8%, but no statistically significant differences were found.Conclusion. It was shown that the perivitelline space pathology of oocytes in the FokI A/G genotype patients is 2.6 times higher, and in the G/G genotype patients – 2.9 times higher than in the A/A genotype patients. However, there were no differences in pregnancy rate among patients with different genotypes of FokI, BsmI and TaqI gene polymorphisms of VDR.