Tehran University Medical Journal

Background: Lots of vitamin D functions are mediated by its steroid family receptor (VDR). Vitamin D role in infertility is reported by significant fertility reduction in many male laboratory animals with vitamin D deficiency. The reason for reduced fertility in male VDR-null mouse model has been reported to be reduced sperm count and sperm motility. Vitamin D has effects on sperm motility, sperm-ovum coupling, and acrosome reaction stimulation. As VDR is expressed in human male reproductive system, the aim of the current study was to investigate the role of rs2228570 polymorphism of VDR gene in male infertility.

Methods: Investigation was done as a case-control study on infertile azoospermic or oligospermic men referring to Avicenna Research Institute from March 2014 to April 2015. Rs2228570 single nucleotide polymorphism (SNP) located in exon 1 of VDR gene was chosen according to its role on protein function. Blood sampling was done on cases and control groups and after DNA extraction the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) reaction was designed and performed on 100 normal cases, 100 azoospermic and 100 oigospermic control samples. Distribution of quantitative age variable was done using Student’s t-test and qualitative variables (genotype and allelic frequencies) was done using SPSS, ver. 22 (Chicago, IL, USA).

Results: Chi-square test didn’t show significant difference between two case groups and controls (Azoosperm and control P=0.5 and oligosperm and control P=0.09). Comparing CC genotype frequency with TT and CT genotypes (azoosperm and control P=0.48 OR=0.77, oligosperm and control, P=0.17 OR=0.77) and in comparing between TT genotype with CT and CC genotypes (azoosperm and control P=0.49 OR=3.03, oligosperm and control P=0.19 OR=7.21) the difference between these groups was not significant and didn’t increase the probability of disease and didn’t show protective role against it.

Conclusion: According to the findings, the association between rs2228570 polymorphism of vitamin D receptor gene and infertility was not significant and investigation of other polymorphisms might show a relationship with male infertility.