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Genetic and Rare Diseases Information Center (GARD)

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MTHFR gene mutation

*

* Not a rare disease

Other Names for this Disease

  • Methylenetetrahydrofolate reductase mutation
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

I have recently been diagnosed with the C677T heterozygous gene mutation. What I would most like to know is: does this mutation have any bearing or is it something I do not need to concern myself with? 

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is a MTHFR gene mutation?

MTHFR gene mutation is a genetic change that disrupts the production of an enzyme that plays an important role in breaking down the amino acid homocysteine (a building block of protein). These mutations may cause a mild to severe loss of activity of this enzyme that can lead to elevated levels of homocysteine in the blood and/or urine.[1][2] Some rare MTHFR gene mutations severely impair the function of this enzyme and lead to homocystinuria, an autosomal recessive condition characterized by various health problems including abnormal clotting and neurological problems (developmental delay, seizures, intellectual disability and microcephaly).[2][3] Other more common MTHFR gene mutations (known as C677T and A1298C) lead to a milder reduction in enzyme function. People with two copies of C677T or one copy of C677T and one copy of A1298C may have an increased risk for cardiovascular conditions such as coronary artery disease, blood clots, and stroke. Although C677T and A1298C mutations can be associated with an increased risk, many people who inherit them will never develop one of the associated conditions.[4][2][1]
Last updated: 12/10/2014

Does having one C677T mutation in the MTHFR gene increase a person's risk of developing blood clots?

Having one mutation in the MTHFR gene is typically not associated with an increased risk of blood clots, because it usually does not lead to high levels of homocysteine in the blood. People with two C677T mutations may have high homocysteine levels, which may be linked with an increased risk for blood clots and hardening of the arteries (atherosclerosis).[1]
Last updated: 12/11/2014

References
Other Names for this Disease
  • Methylenetetrahydrofolate reductase mutation
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.