Analysis of VDR gene polymorphism Fok1 in infertile women with endometriosis - Revista Brasileira de Ginecologia e Obstetrícia

PURPOSE: to evaluate the frequency of VDR gene polymorphism Fok1 in infertile women with endometriosis and Control and its relation to the disease. METHODS: a case-control study that included 147 infertile women with endometriosis and 154 fertile women without endometriosis as Control. Fok1 polymorphism (rs10735810, T2C), which promotes a T/C exchange in exon 2 of the VDR gene, was identified by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), that involves the combination of amplification by PCR and digestion with restriction endonuclease. The χ2 test was used to compare allele and genotype frequencies between groups. All p-values were two-tailed and a p-value < 0.05 was considered statistically significant. RESULTS: the TT, TC and CC genotype frequencies of VDR Fok1 polymorphism were 44.2%, 46.9% and 8.9% in infertile women with endometriosis and 41.6%, 50% and 8.4% in the Control Group. No significant difference was found (p=0.8), even when the patients were subdivided according to the stage of endometriosis (p=0.3 for minimal and mild endometriosis and p=0.2 for moderate and severe endometriosis). Alleles T and C were present, respectively, in 67.6% and 32.3% of infertile women with endometriosis (p=0.8), in 63.5% and 36.5% of women with minimal/mild endometriosis (p=0.5), in 72.5% and 27.5% of women with moderate/severe endometriosis (p=0.2), and in 66.6% and 33.4% of the Control Group. No statistically significant difference was found among any groups and the Control. CONCLUSION: the results suggest that VDR gene polymorphism Fok1 does not confer genetic susceptibility to endometriosis-associated infertility in the Brazilian population.