One-carbon metabolism and folate transporter genes: Do they factor prominently in the genetic etiology of neural tube defects?

Abstract

Neural tube defects (NTDs) are a broad class of congenital birth defects that result from the failure of neural tube closure during neurulation. Folic acid supplementation has been shown to prevent the occurrence of NTDs by as much as 70% in some human populations, and folate deficiency in a pregnant woman is associated with increased risk for having an NTD affected infant. Thus, folate transport-related genes and genes involved in the subsequent folate-mediated one-carbon metabolic pathway have long been considered primary candidates to study the genetic etiology of human NTDs. Herein, we review the genes involved in folate transport and one-carbon metabolism thus far identified as contributing variants that influence human NTD risk, and place these findings in the context of our evolving understanding of the complex genetic architecture underlying these defects.

Keywords: Folate transporters; Genomics; Neural tube defects; One-carbon metabolism.

Figure 1.. Overview of folate one carbon metabolism

Transport of folates into the cytosol and mitochondria are depicted by the blue and red circles respectively. Compartmentalization of one carbon metabolism between the cytosol and mitochondria is demonstrated, with key enzymes participating in one carbon reactions displayed in gold font. The Glycine Cleavage System (GCS) includes the enzymes AMT and GLDC. Carbon units, carbon donors, and carbon acceptors are displayed in purple font. CH3-THF = 5-methyl-THF, CH2-THF = 5,10-methylene-THF, CH⁺-THF = 5,10-methenyl-THF, CHO-THF = 10-formyl-THF. *This figure was modified from our collaborators’ in Momb et al. 2013.