Polymorphisms of 5, 10-Methylentetrahydrofolate Reductase (MTHFR C677T) and Methionine Synthase Reductase (MTRR A66G) as Maternal Risk Factors for Fetal Aneuploidy

ABSTRACT

PURPOSE: Aneuploidy is the cause of diseases such as Down syndrome or Edward syndrome and, more generally, is a major cause of mental retardation and fetal loss. The purpose of this study was to evaluate the association between MTHFR (C677T) or MTRR (A66G) polymorphisms and fetal aneuploidy. MATERIALS AND METHODS: Data was collected from 37 women who had a fetus with aneuploidy (cases) and 78 women who had previously delivered at least two healthy children without aneuploidy and did not have a history of miscarriage or abnormal pregnancy (controls). The MTHFR (C677T) or MTRR (A66G) polymorphisms were analyzed by PCR-restriction fragment length polymorphism assay. RESULTS: The frequencies of the MTHFR 677 CC, CT, and TT genotypes were 30.7%, 48.7%, and 20.6% in the control group and 37.8%, 48.6%, and 13.5% in the case group, respectively. There were no significant differences in genotype frequencies between the two groups. For the MTRR A66G polymorphism, the frequencies of the AA, AG and GG genotypes were 50%, 46.1%, and 3.9% in the control group and 13.5%, 81.1%, and 5.4% in case group, respectively. The frequency of the MTRR AG mutant was significantly increased in the case group, with an odds ratio of 6.5 (95% CI 2.3-18.6, P<0.05). CONCLUSION: The results of this study suggest that mother carriers with the MTRR G allele have an increased risk of fetal aneuploidy, while the MTHFR T allele is not associated with increased risk of fetal aneuploidy. The MTRR A66G polymorphism may be a risk factor for producing a child with chromosomal aneuploidy.