MTHFR (methylenetetrahydrofolate reductase) is a key enzyme in the process of folate metabolism, which can catalyze the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate (5-MTHF), as an indirect donor of methyl groups, then participate in the synthesis of purines and pyrimidines and the methylation of DNA, RNA, and proteins in the body, maintaining normal homocysteine levels in the body.
MTHFR has genetic polymorphisms, and the most likely mutation site is C677T.
The MTHFR C677T mutation can significantly decrease the activity of MTHFR enzyme, and there are the following three genotypes.
Genotype |
MTHFR activity |
Folate metabolism disorder |
677CC |
100% |
Normal |
677CT |
65% |
Moderate risk |
677TT |
30% |
High risk |