 Multiple studies have demonstrated the highly melanized integument as a defense against folate photolysis in native Americans or African Americans correlates with lower occurrence of NTDs in general.A deficiency of folate itself does not cause neural tube defects.The association seen between reduced neural tube defects and folic acid supplementation is due to a gene-environment interaction such as vulnerability caused by the C677T Methylenetetrahydrofolate reductase (MTHFR) variant.