We concluded that RFC-1 and CBS gene mutation alleles are related to Down syndrome, and women with mutation RFC-1 G80G, CBS C833C OR combined with RFC-1A80G and CBS 833TT genotype increase the risk of Down syndrome in China.
Therefore, we carried out a meta-analysis of 26, 17, 9, 15, 9 and 6 case-control studies on the relationship between maternal methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase (MTR) A2756G, methionine synthase reductase (MTRR) A66G, reduced folate carrier 1A80G and cystathionine β-synthase 844ins68 polymorphisms and the risk of having a DS offspring.
Present results suggest that the maternal RFC-1 80A>G polymorphism might be associated with an increased risk of having a birth with DS, particularly among carriers of the GG genotype.
In a group of 121 case families (mother, father, and proband with DS and AVSD) and 122 control families (mother, father, and proband with DS and no CHD), tag SNPs were genotyped in and around five folate pathway genes: 5,10-methylenetetrahyrdofolate reductase (MTHFR), methionine synthase (MTR), methionine synthase reductase (MTRR), cystathionine beta-synthase (CBS), and the reduced folate carrier (SLC19A1, RFC1).
The results show that individual polymorphisms studied in this work are not associated with DS; however, the effects of the combined risk genotypes among MTR, MTRR, CBS and RFC genes are considered maternal risk factors for DS offspring in our population.
In conclusion, the presence of three or more polymorphic alleles for MTHFR C677T, MTHFR A1298C, MTR A2756G, and RFC1A80G, and plasma Hcy concentrations higher than 4.99 micromol/L are maternal risk factors for DS.
The aim of the present study was to evaluate chromosome damage, measured by means of the micronucleus assay, in peripheral lymphocytes of a group of women (n = 34) who had a DS child in young age (<35 years) and in a control group (n = 35), and to correlate them with MTHFR 677C > T and 1298A > C, RFC-1 80G > A and MTR 2756A > G polymorphisms.
Present results seem to indicate that none of the RFC-1 80G>A, MTHFR 677C>T, and MTHFR 1298A>C polymorphisms is an independent risk factor for a DS offspring at a young maternal age; however, a role for the combined MTHFR/RFC-1 genotypes in the risk of DS pregnancies among young Italian women cannot be excluded.
The purpose of the present study was to analyse these findings among the French population and to investigate whether common polymorphisms in genes of the folate and homocysteine pathway, including the MTHFR 677C > T, MTHFR 1298A > C, the methionine synthase (MTR) 2756A > G, the cystathionine beta-synthase (CBS) 844Ins68 and the reduced folate carrier (RFC-1) 80G > A polymorphisms, contribute to the risk of trisomy 21.