Metabolic effects and the methylenetetrahydrofolate reductase (MTHFR) polymorphism associated with neural tube defects in southern Brazil

Abstract

Despite the small sample in this study, we suggest that low vitamin B12 and, consequently, hyperhomocysteinemia are important risk factors for NTDs in our population.

Methylenetetrahydrofolate reductase gene polymorphisms and the risk of anencephaly in Mexico

“…C polymorphism and anencephaly our results are consistent with those reported by other authors of the region (Barber et al, 2000;Felix et al, 2004) and do not support the results of van der Put who found that the heterozygotic combination 677T/1298C was more common among patients affected by NTDs than among their controls (van der Put et al, 1998). De Marco et al (2002) found that among the Italian population, both heterozygosity and maternal homozygosity for the mutated 1298C allele, increased the risk of DTN, this being to date the only study which found such this association.…”

“…T mutation (van der Put et al, 1995;Shields et al, 1999;Kirke et al, 2004) whereas others do not find this association (Barber et al, 1999;Lucock et al, 2000, Felix et al, 2004. Studies which have evaluated the association between the 1298C allele and NTDs are less common and the results reported to date have been inconsistent (van der Put et al, 1998;Felix et al, 2004;De Marco et al, 2002).…”

Assessing the association between the methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism and blood folate concentrations: a systematic review and meta-analysis of trials and observational studies

“…However, a community intervention program in China showed that high-compliance use of 400 mg of folic acid/d did result in neural tube defect birth prevalence in a population with a high TT genotype prevalence that was similar to a population with low TT genotype prevalence (57,60). There is limited evidence to conclude whether a mandatory folic acid fortification program could mitigate the risk conferred by the polymorphism (61)(62)(63). More research is needed to understand how to bridge gaps in blood folate concentrations because of the MTHFR 677C.T polymorphism.…”

Effect on risk of anencephaly of gene–nutrient interactions between methylenetetrahydrofolate reductase C677T polymorphism and maternal folate, vitamin B12and homocysteine profile

“…The 677C-T mutation causes an alanine to valine substitution in the predicted catalytic domain of MTHFR, rendering the enzyme thermolabile, with reduced activity under conditions of low folate concentrations (15) . Homozygosity for the 677T allele is associated with an increase in plasma Hcy levels and a decreased methyltetrahydrofolate pool, predominantly in states of folate, cobalamin and riboflavin (vitamin B 2 ) deficiency (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) . The other polymorphism, 1298A-C, which leads to substitution of an adenine by a cytosine, has also been associated with decreased MTHFR enzyme activity, although not as pronounced as that caused by the 677C-T polymorphism (18,20,21) .…”