MTHFR Gene Test

An MTHFR gene test checks a sample of your blood for two very common changes in a gene called MTHFR. Changes in your genes are also called gene variants or mutations. Genes are parts of DNA in your cells that you inherit from your parents.

You inherit two copies of each gene, one coming from each parent. Genes carry information that controls what you look like and how your body works. The MTHFR gene provides instructions for making the MTHFR protein.

This protein helps your body use folate, a type of B vitamin that you get from various foods. Normally, your body uses folate and other B vitamins to break down an amino acid called homocysteine. Because of this, only small amounts of homocysteine stay in your bloodstream.

If you have a change in the MTHFR gene, however, the MTHFR protein may not process folate as well as it should. As a result, you may have increased levels of homocysteine in your blood. In general, medical researchers aren't certain that increased homocysteine levels directly cause health problems.

However, some studies have shown that they can damage the inside of your blood vessels. This may increase the risk for blood clots, heart disease, and stroke. Higher homocysteine levels during pregnancy can also increase the risk of having: A baby with neural tube defects.; Early pregnancy loss (a miscarriage).; Preeclampsia.; To lower homocysteine levels, your health care provider will usually recommend taking vitamin B supplements that include folic acid, which is a form of folate.

However, if you have the gene variant MTHFR, your provider may recommend methylfolate (5-MTHF) instead since your body may be able to use this form more easily. The extra vitamins can make up for an MTHFR gene that's not fully working. Your provider may recommend eating more foods with folate, too.

Before making changes in your health habits, talk with your provider. Studies show that taking folic acid greatly reduces the risk of neural tube defects in babies. So, even if you have the MTHFR gene variant, the U.S.

Centers for Disease Control and Prevention (CDC) recommends folic acid supplements for everyone who may become pregnant.

Why this test is done

Medical experts do not recommend testing for common MTHFR gene changes in most cases. However, your provider may order this test if you had a blood test that showed higher than normal levels of homocysteine and:

• A close relative was diagnosed with an MTHFR gene change.
• You and/or close family members have early heart or blood vessel disease.

You may also need an MTHFR gene test if your provider prescribes a medicine called methotrexate. Methotrexate is used to treat certain types of cancer, psoriasis, and rheumatoid arthritis. The MTHFR protein helps your body use this medicine properly.

The results of a MTHFR gene test may help your provider choose the dose that will be safe for you.

How to prepare

You don't need any special preparations for an MTHFR gene test.

Sample type

Blood

Other names for this test

methylenetetrahydrofolate reductase mutation, C677T and A1298C, MTHFR DNA assay, MTHFR DNA testing, MTHFR gene variants, MTHFR gene polymorphisms 677T>C & 1298A>C mutations