Objective: To assess the association of C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene with the susceptibility to polycystic ovary syndrome (PCOS).
Methods: Blood samples of 115 PCOS patients and 58 fertile women (for whom PCOS has been excluded) were collected for DNA extraction. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for determining the C677T and A1298C polymorphisms. A database has been set up with Epidata and a significance test was performed with a statistical analysis system.
Results: A significant difference has been found in the allele frequencies of MTHFR gene 677 C and T polymorphisms between the two groups (P<0.01), for which T allele has increased the risk for PCOS by 2.06 times. Heterozygous and homozygous genotypes at position 677 (CT and TT) were more common among PCOS cases than controls, with an OR of 3.91 (95%CI: 1.70-8.97) and 4.39 (95%CI: 1.77-10.89), respectively. There was no statistical difference in genotypic distribution of MTHFR gene A1298C polymorphism (P>0.05). In the PCOS group, there was a significant difference with an OR of 6.40 (95%CI: 1.71-23.95) for an increased risk of insulin resistance in homozygous C677T mutations (TT) compared with the wild genotype (CC, P<0.01). The PCOS group and the control group also differed significantly in their red blood cell folate levels (P<0.01), but not in serum vitamin B12 and homocysteine levels (P>0.05).
Conclusion: MTHFR gene C677T polymorphism is associated with PCOS, for which CT and TT genotypes can increase the risk of PCOS. The TT genotype can also increase the risk of insulin resistance in PCOS patients. The A1298C polymorphism of the MTHFR gene is not associated with the occurrence of PCOS. The folate level in red blood cells of PCOS patients is lower, for whom folate should be supplemented.