However, the binary logistic regression showed a higher frequency of the polymorphic homozygote genotype in DS parent group to codominant and dominant model in the RFC1A80G.
The combined presence of RFC1 mutant alleles and the CBS homozygous mutant allele (15/104) was associated with a 4.81-fold increased risk of having a child with Down syndrome (95 % CI 1.82-12.68, P = 0.0007).
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.
This study aimed to analyze a dataset of genetic and cytogenetic data in an Italian group of MDS and mothers of healthy children (control mothers) to assess the predictive capacity of artificial neural networks assembled in TWIST system in distinguish consistently these two different conditions and to identify the variables expressing the maximal amount of relevant information to the condition of being mother of a DS child.The dataset consisted of the following variables: the frequency of chromosome damage in peripheral lymphocytes (BNMN frequency) and the genotype for 7 common polymorphisms in folate metabolic genes (MTHFR 677C>T and 1298A>C, MTRR 66A>G, MTR 2756A>G, RFC1 80G>A and TYMS 28bp repeats and 1494 6bp deletion).
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 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 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.
Increased risk of Down syndrome was associated with the methylenetetrahydrofolate reductase (MTHFR) 1298C allele (OR 1.46; 95% CI 1.02-2.10), the MTHFR 1298CC genotype (OR 2.29; 95% CI 1.06-4.96), the reduced-folate-carrier1 (RFC1) 80G allele (1.48; 95% CI 1.05-2.10) and the RFC1 80 GG genotype (OR 2.05; 95% CI 1.03-4.07).