Association of vitamin D receptor gene polymorphisms, metabolic features and susceptibility to polycystic ovary syndrome: a preliminary study.

Research Question: Are the combined genotypes and haplotypes of vitamin D receptor (VDR) gene polymorphisms (FokI, ApaI and TaqI) associated with susceptibility to polycystic ovary syndrome (PCOS) and metabolic features of the disease?

Design: This case-control study included 46 women with PCOS and 48 controls. Genotypes of the VDR gene were determined using the polymerase chain reaction-restriction fragment length polymorphism method. Waist circumference, and parameters of lipid and glucose metabolism were evaluated in all women.

Results: Women in the PCOS group had a larger waist circumference (P = 0.0383) and a higher visceral adiposity index (VAI) (P < 0.0001) compared with controls. Total cholesterol (P < 0.0001), high-density lipoprotein cholesterol (P = 0.00001) and triglyceride (P < 0.0001) concentrations were higher in the PCOS group. The VDR-FokI C/C (F/F) genotype was associated with significantly higher odds of PCOS (adjusted OR 6.27, 95% CI 1.53-25.65). The VDR-ApaI genotype was associated with susceptibility to PCOS in the dominant model; the variant genotypes [A/C + A/A (A/a + a/a)] had higher odds of PCOS than the wild genotype [C/C (A/A)] (adjusted OR 3.15, 95% CI 1.07-9.32). Haplotype analysis revealed that the T-C-T (f-A-T) haplotype was significantly associated with lower odds of PCOS (adjusted OR 0.10, 95% CI 0.01-0.95). Women with PCOS carrying the VDR-FokI T/T (f/f) genotype had lower fasting glucose (P = 0.0469) and higher VAI (P = 0.0406) compared with women with the C/T (Ff) + C/C (F/F) genotype.

Conclusion: The present findings suggest an association between FokI and ApaI polymorphisms and PCOS susceptibility. Moreover, the VDR-FokI T/T (f/f) genotype could be a marker for decreased fasting glucose in women with PCOS. No association was found between the TaqI polymorphism and PCOS susceptibility in the study population.