Neural tube defects: prevention by folic acid and other vitamins.

Neural Development Unit, Institute of Child Health, University College, London, 30 Guilford Street, London WC1N 1EH.
The Indian Journal of Pediatrics (Impact Factor: 0.72). 01/2001; 67(12):915-21. DOI: 10.1007/BF02723958
Source: PubMed

ABSTRACT Folic acid has been demonstrated in clinical trials to reduce significantly the recurrence (and probably occurrence) of neural tube defects (NTD). In the U.K., there has been no decline in prevalence of NTD since the publication of the findings with folic acid. This article examines a series of questions relating to the action of folic acid, with emphasis on the use of mouse models as a source of experimental information which cannot easily be obtained by direct study of humans. Several mouse genetic NTD models exhibit sensitivity to prevention by folic acid, whereas other mice which develop morphologically similar NTD are resistant. Folic acid normalises neurulation in the sensitive mouse strains, providing evidence for a direct effect on the developing embryo, not on the pregnant female: Mouse studies do not support the proposed action of folic acid in encouraging the in utero demise of affected fetuses (i.e. terathanasia). Polymorphic variants of several folate-related enzymes have been shown to influence risk of NTD in humans and an inherited abnormality of folate metabolism has been demonstrated in one mouse NTD model. However, the biochemical basis of the action of folic acid in preventing NTD remains to be determined in detail. NTD in one folate-resistant mouse strain can be prevented by myo-inositol, both in utero and in vitro, raising the possibility of a therapeutic role also in humans. Gene-gene interactions seem likely to underlie the majority of NTD, suggesting that poly-therapy involving folic acid and other agents, such as myo-inositol, may prove more effective in preventing NTD than folic acid treatment alone.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hyperhomocysteinemia in humans is a risk factor for adverse pregnancy outcome, especially congenital malformations. This review summarizes the studies directed on the teratogenicity of homocysteine carried out in animal studies, and elaborates on the underlying mechanisms. Literature was searched in Pubmed (NCBI) through January 2010 and selected manually. Keywords comprised homocysteine, congenital abnormalities and animals. Increased frequencies of a wide range of congenital malformations are reported especially in the chicken embryo after exposure to homocysteine (Hcy) in various dosages and forms. Reduced embryonic growth and abnormalities of the vascularization of the yolk sac are described in mouse studies. A study in rats revealed a reduced development of blastocysts. The congenital malformations observed in the chicken embryo model share the mutual involvement of Hcy sensitive neural crest cells. Derangements in the behavior of these cells by interactions between Hcy and pathways involved in vascularization, growth, metabolism, signaling, and DNA synthesis and methylation may explain the wide range of effects on embryonic organs, the yolk sac and placental tissues. The associations between human hyperhomocysteinemia and congenital malformations are substantiated by chicken and rodent studies. Moreover, derangements of several pathways induced by Hcy are demonstrated with adverse effects on both reproduction and long term health. Because of the high prevalence of hyperhomocysteinemia in both the reproductive and general population, research on underlying epigenetic mechanisms is warranted.
    Reproductive Toxicology 12/2010; 30(4):520-31. · 3.14 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Periconceptional supplementation with folic acid has led to a significant worldwide reduction in the incidence of neural tube defects (NTDs). However, despite increasing awareness of the benefits of folic acid supplementation and the implementation of food fortification programs in many countries, NTDs continue to be a leading cause of perinatal morbidity and mortality worldwide. Furthermore, there exists a significant subgroup of women who appear to be resistant to the protective effects of folic acid supplementation. The following review addresses emerging clinical and experimental evidence for a role of the immune system in the etiopathogenesis of NTDs, with the aim of developing novel preventative strategies to further reduce the incidence of NTD-affected pregnancies. In particular, recent studies demonstrating novel roles and interactions between innate immune factors such as the complement cascade, neurulation, and folate metabolism are explored. Birth Defects Research (Part A) 97:602-609, 2013. © 2013 Wiley Periodicals, Inc.
    Birth Defects Research Part A Clinical and Molecular Teratology 09/2013; 97(9):602-9. · 2.27 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We compared individual trait variability in 65 male and 81 female patients with spina bifida occulta (SBO) or spina bifida aperta (SBA) against 170 male and 200 female subjects randomly selected Serbian subjects without these conditions. Variability was evaluated by direct observation of 15 homozygous recessive traits (HRT), while gender was evaluated separately. Individual trait variations between genders in SBO patients (4/15 HRT) and in SBA patients (12/15 HRT) showed remarkable differences. Individual trait variations between the male control group and SBO (9/15 HRT), between the female control group and SBO (5/15 HRT), between the male control group and SBA (8/15 HRT), between the female control group and SBA (9/15 HRT), between male SBO and SBA patients (6/15 HRT), between female SBO and SBA patients (6/15 HRT), also indicated remarkable differences. These differences could be explained by different expression of genes that may contribute to expression of spina bifida (SB).
    Balkan Journal of Medical Genetics 06/2011; 14(1):11-8. · 0.08 Impact Factor


Available from
May 30, 2014