Dietary folic acid supplementation is known to dramatically reduce incidence of neural tube defects such as spina bifida and anencephaly, sometimes by as much as 70 percent. Scientists and other health experts still don’t fully understand how folic acid does this, or why it doesn’t eliminate birth defects in all pregnancies.

Folic acid was originally discovered at The University of Texas (UT) at Austin in the 1940s. Ever since the discovery of its role in the prevention of birth defects, all enriched cereal grain products in the U.S. were enriched with folic acid to ensure that women of childbearing age get enough of this vitamin.

Now, scientists from the College of Natural Sciences at UT Austin have found that mutation of a key folic acid enzyme causes neural tube defects in mice, the clearest link seen so far between folic acid and birth defects.

The mice used in this study lacked a gene for a folic acid enzyme which cells need to produce a compound called formate, which embryos need for normal development. It seems folic acid prevents birth defects by ensuring that enough formate is made in the developing embryo. This may also explain the 30 percent of neural tube defects that can’t be prevented by folic acid supplementation.

Interestingly, humans share the same gene for the folic acid enzyme with all mammals - indeed, point mutations in this gene are known to increase the risk of birth defects.

Now the research team at UT Austin is going to use the same breed of mouse to start looking for nutrients that could potentially be delivered to pregnant mothers to prevent neural tube defects that can’t be prevented by folic acid supplementation.

A future goal would be to screen women for the gene that produces the folic acid enzyme. If they’re found to be deficient, their chances for developing embryos free of neural tube defects could be increased via nutrient supplementation.


Mutation in key enzyme in key folic acid metabolism causes birth defects.