MTHFR is an enzyme that catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, the primary circulating form of folate and co-substrate for homocysteine remethylation to methionine. The 677 C>T variant has been linked to an increased incidence of various diseases such as CVD (stroke, atherosclerosis), Down’s syndrome, neural tube defects, psychiatric (schizophrenia, bipolar, major depressive disorder) or cognitive disorders (dementia) and cancers.
If you have the TT genotype in this gene, then your enzyme activity is approximately only 64% compared to the CC genotype. You may be predisposed to higher blood homocysteine, lower folate and riboflavin levels. Add in optimal intake of folate, choline, and vitamins B6 and B12. You may require as much as 400-800ug/day folate depending on the source. Quality supplements, in a bioactive form, may be required. This genotype has been associated with several diseases such as arterial disease, cardiovascular disease, infertility, birth defects, psychiatric or cognitive disorders, and certain cancers. When planning your daily health choices, it would be a good idea to consider your MTR, MTRR, COMT and APOE genotypes too.