Birth defects are among the leading pediatric healthcare issues, yet there are few prevention strategies and the prevalence of birth defects in the US has remained relatively stable for decades, despite folic acid fortification of the food supply. Neural tube defects (NTDs) are among the most common and serious of all birth defects affecting 0.5-1 per 1,000 US newborns, yet their complex etiology remains poorly understood (Wallingford et al., 2013). It is well established that pre-pregnancy supplementation with folic acid can reduce the risk of NTDs, but the underlying mechanism of this beneficial effect is unclear. Approximately 30% of NTDs cannot be prevented by maternal periconceptional folate supplementation. Our preliminary data showed that rare mutations in planar cell polarity (PCP) pathway could increase the risk of NTDs, while mutagens such as polycyclic aromatic hydrocarbons were enriched in the placentas of NTDs fetuses/infants. We hypothesized that NTDs are caused by combinations of rare multiple mutations. Higher mutation rates results in a higher NTDs prevalence. It is possible that folic acid can prevent NTDs by reducing the mutation rate. Furthermore, we hypothesize that paternal supplementation with folic acid can further reduce NTD rates. We have a unique opportunity to evaluate folate supplement effect on mutation rate by leveraging previously collected biological samples from NTD patients and controls from several distinct cohorts. Additionally, we propose to use mouse models to better understand the relationship between folate and mutation rates in vivo. The results of this study will provide an explanation of how folate prevents NTDs, and will reveal novel pathways for intervention on folate-resistant NTDs. Hence, the successful completion of the proposed studies is likely to have substantial impact on our understanding of conditions that affect ~6% of births worldwide and constitute one of the major healthcare concerns for the youngest members of society.

Public Health Relevance

Folic acid supplementation has proven to be an effective intervention in the prevention of neural tube defects (NTDs). Despite decades of investigation, it is far from clear how this beneficial effects is achieved, and why over 30% of remaining cases of NTDs are not folate responsive. We hypothesize that folic acid reduces the mutation rates, thereby limiting combinations of rare mutations that have been associated with increase NTD risks. We believe that paternal supplementation with folic acid can further reduce NTD prevalence. These hypotheses will be tested in human NTD samples as well as in newly developed mouse model systems.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
7R01HD081216-04
Application #
9625376
Study Section
Pregnancy and Neonatology Study Section (PN)
Program Officer
Henken, Deborah B
Project Start
2015-08-10
Project End
2020-06-30
Budget Start
2017-09-01
Budget End
2018-06-30
Support Year
4
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
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Tian, Tian; Wang, Linlin; Shen, Yan et al. (2018) Hypomethylation of GRHL3 gene is associated with the occurrence of neural tube defects. Epigenomics 10:891-901

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