[Association of MTHFR and MTRR genes polymorphisms with non-disjunctions of chromosomes 18 and 21].

OBJECTIVE

To explore the effect of MTHFR and MTRR genes polymorphisms on chromosomes 18 and 21 non-disjunction through investigation of Henan Han Chinese young females with a gestational history of trisomy 21 (Down syndrome, DS) or trisomy 18 (Edwards syndrome, ES).

METHODS

Polymorphisms of MTHFR 677C/T, MTHFR 1298A/C and MTRR 66A/G were analyzed in 73 healthy females (controls group), 78 females with a gestational history of DS (DS group) and 54 females with a gestational history of ES (ES group) by direct sequencing of PCR products from amplification of peripheral blood lymphocyte DNA.

RESULTS

The frequency of MTHFR 677T allele was significantly different among the DS group, ES group and the control group (P<0.05). The frequency of MTRR 66G allele was significantly different only between the DS group and the control group (P<0.05). MTHFR 1298A/C polymorphisms were not associated with either ES or DS. Compared with the wild genotype MTHFR 677CC or MTRR 66AA, carriers of the MTHFR 677CT, 677TT, or MTRR 66GG genotypes had respectively 2.694 times (95%CI: 1.204-6.025, P<0.05), 5.451 times (95%CI: 2.211-13.435, P<0.05) and 9.618 times (95%CI: 2.085-44.365, P<0.05) risk of bearing a DS baby. Compared with the wild genotype MTHFR 677CC, carriers of the MTHFR 677CT and 677TT genotype had respectively 2.701 times (95%CI: 1.133-6.438, P<0.05) and 3.804 times (95%CI: 1.406-10.293, P<0.05) risk of bearing a ES baby. Neither MTRR 66AG or 66GG genotype was associated with the occurrence of ES.

CONCLUSION

The MTHFR 677T and MTRR 66G may represent a risk factor for DS gestation, while MTHFR 677T may represent a risk factor for ES gestation for Chinese Han females.