Abstract
Recent evidence shows that almost 92% of the DS children are born from young mothers, suggesting that other risk factors than advanced maternal age must be involved. In this context, some studies demonstrated a possible link between DS and maternal polymorphisms in genes involved in folate metabolism. These polymorphisms, as well as low intake of folate could generate genomic instability, DNA hypomethylation and abnormal segregation, leading to trisomy 21. We compared the frequency ofCBS844ins68,MTR2756A>G,RFC-1 80G&gt A andTC776C>G polymorphisms among 114 case mothers and 110 matched controls, in order to observe whether these variants act as risk factors for DS. The genotype distributions revealed that there were not significant differences between both samples. However, when we proceed the multiplicative interaction analyses between the four polymorphisms described above together with the previously studiedMTHFR677C>T,MTHFR1298A>C andMTRR66A>G polymorphisms, our results show that the combined genotypeTC776CC /MTHFR677TT andTC776CC /MTR2756AG were significantly higher in the control sample. Nevertheless, there was no significant association after Bonferroni correction. Our results suggest that maternal folate-related polymorphisms studied here have no influence on trisomy 21 susceptibility in subjects of Brazilian population.
Highlights
Trisomy 21 is the most common genetic cause of mental retardation and occurs with a prevalence of 1 in 800 live births [15]
Despite the fact that Down syndrome (DS) was described almost 150 years ago, little is known about the mechanisms that lead to trisomy of chromosome 21
We investigated the relationship of cystathionine-beta-synthase (CBS) 844ins68, methionine synthase (MTR) 2756A>G, reduced folate carrier (RFC-1) 80G>A and transcobalamin (TC) 776C>G polymorphisms on the risk of having a DS child, as well as, the interaction between these polymorphisms and the MTHFR 677C>T, MTHFR 1298A>C and MTRR 66A>G polymorphisms, previously studied by our group [23]
Summary
Trisomy 21 is the most common genetic cause of mental retardation and occurs with a prevalence of 1 in 800 live births [15]. Despite the fact that advanced maternal age (>35 years) is a major risk factor for DS, recent evidence shows that almost 92% of children with this disease are born from mothers at a young age (G, reduced folate carrier (RFC-1) 80G>A and transcobalamin (TC) 776C>G polymorphisms on the risk of having a DS child, as well as, the interaction between these polymorphisms and the MTHFR 677C>T, MTHFR 1298A>C and MTRR 66A>G polymorphisms, previously studied by our group [23]
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