Methylenetetrahydrofolate reductase (MTHFR) gene provides the body with instructions regarding the creation of an enzyme that is involved in the process of breaking down an amino acid called homocysteine. High levels of homocysteine are associated with heart disease, kidney disease, and low levels of vitamins B6, B12, and folate. Humans carry two copies of the MTHFR gene, one inherited from the mother and one from the father, and as with any gene, mutations or variants can occur. A person can have one MTHFR gene mutation, inherited from one parent, or two MTHFR gene mutations, inherited from both parents.
Studies show that women with one MTHFR gene mutation, called C677T, have an increased risk of having a child with a neural tube defect. Women with two C677T mutations are twice as likely to have a child with a neural tube defect. This increased risk is due to the association between the gene mutation and folate deficiency. Women with a MTHFR gene mutation who supplement with synthetic folate should look for methylfolate (5-methyl-THF) in their supplements, as it is easier to absorb than folic acid.
Genetic testing for MTHFR gene mutations is available. [43]