Oct 12, 2023
Vitamin B9 is represented by the folate group, whose structure is derived from folic acid. It serves as an essential cofactor in methylation reactions and the synthesis of purines and pyrimidines, and the main sources of folate in the diet are green leafy vegetables, legumes, meat products and grains. However, the folic acid form is not active in the human body and must be converted by the liver into the active molecule, 5-methyltetrahydrofolate (5-MTHF). Folate deficiency is associated with hyperhomocysteinemia, megaloblastic anemia, cardiovascular disease, especially neural tube defects, and cognitive impairment (Ferrazzi E, Tiso G, Di Martino D., 2020).
Folate and MTHFR Gene Relationship
The MTHFR gene encodes the information needed to produce an enzyme called methylenetetrahydrofolate reductase. This enzyme is important for processing amino acids and creating proteins. The MTHFR enzyme is also required for folate metabolism. Folate, activated by the addition of a methyl group, is required for the conversion of homocysteine to methionine. Methionine is important for the production of protein and other compounds in the body. Genetic variations in the MTHFR gene result in decreased activity of the enzyme and are associated with a number of diseases and conditions, including cardiovascular disorders, neurological defects, certain types of cancer, psychiatric disorders, diabetes, and pregnancy complications (W Boughrara et al., 2015).
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The table above contains the gene (MTHFR) and its polymorphisms that are important in folate metabolism. The common C677T variant and the A1298C variant in the folate-metabolizing MTHFR gene are the two best-known genetic factors affecting folate status. The MTHFR enzyme catalyses the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate irreversibly. This enzyme is critical for folate metabolism while providing re/methylation of homocysteine. Consequently, individuals with these variants have lower enzyme activity (Hiraoka M. ve Kagawa Y., 2017; Boughrara W. et al.; 2015). In these variants, individuals carrying the C and T risk alleles need more Folate than other individuals. Eventually, they need to take active form of folate.
REFERENCES
Ferrazzi E, Tiso G, Di Martino D. Folic acid versus 5- methyl tetrahydrofolate supplementation in pregnancy. Eur J Obstet Gynecol Reprod Biol. 2020 Oct;253:312-319. doi: 10.1016/j.ejogrb.2020.06.012. Epub 2020 Jun 13. PMID: 32868164
Hiraoka M, Kagawa Y. Genetic polymorphisms and folate status. Congenit Anom (Kyoto). 2017 Sep;57(5):142-149. doi: 10.1111/cga.12232. Epub 2017 Jul 20. PMID: 28598562; PMCID: PMC5601299
W Boughrara, M Aberkane, M Fodil, A Benzaoui, S Dorgham, F Zemani, C Dahmani, E Petit Teixeira, A Boudjema. Impact of MTHFR rs1801133, MTHFR rs1801131 and ABCB1 rs1045642 polymorphisms with increased susceptibility of rheumatoid arthritis in the West Algerian population: A case-control study. Acta Reumatol Port. Oct-Dec 2015;40(4):363-71