MTFR Myths and Reality

MTHFR Myths 

Importance of MTHFR
The MTHFR gene is responsible for making a functional MTHFR enzyme.
If the MTHFR gene is mutated, the enzyme’s function is impaired
MTHFR enzyme must be perfect in order for it to function properly
Dysfunctional MTHFR enzyme may lead to health problems.

Health Problems Associated with MTHFR
Alzheimers Dz
Cardiac Disease
Food Allergies and Celiac Disease
Less severe issues associated with MTHFR
Thyroid Problems
Chronic Fatigue and other Fatigue type Illnesses
Drug Sensitivities

Reality of MTHFR:

What is it?
The gene is responsible for making an enzyme that is important to metabolize folate (also known as folic acid or vitamin B9). It also helps cells recycle homocysteine (a chemical in the blood) into methionine (a building block for protein). There are two naturally occurring variants in this gene. They are the C677T and A1298C. 

When those two variants are present, the resulting MTHFR enzyme is less active, and this can lead to decreased levels of folate and increased levels of homocysteine in the blood. 

The science: 

The methylenetetrahydrofolate reductase gene (MTHFR) ha had people make claims about it that it causes a variety of health problems and neurological conditions. These conditions include blood clots, cancer, migraines and many more. The myth of having one or two copies of the MTHFR variant can lead to those health problems. It is very unlikely that variants of a single gene could cause over a dozen unrelated health problems. In some ethnicities, more than 50% of people have at least one copy. Most genetic causing genetic variants are not this common. 

Another myth is that people who carry an MTHFR variant should avoid foods that are fortified with folic acid. There is no evidence of this at all. Over the past 20 years, scientists have examined the association between MTHFR C677T and A1298C and 600 medical conditions. The evidence has been inconclusive or conflicting. There is no scientific evidence supporting the claims. 

There is one exception. Women with two copies of the 6C77T variant appear to have a slightly increased risk of having a child with a neural tube defect like spina bifida. According to the National Institute of Child Health and Human Development, supplementing with folic acid reduces the risk of neural tube defects in all pregnant women, including those with the variant. 

After a lot of research, existing scientific data does not support this claim of this common variant of the gene. 

*There is a very rare variant of the MTHFR that can cause a severe condition called homocystinuria. It affects fewer than 1 in 200,000 people in most ethnicities. 


[1]Levin BL et al. (2016). “MTHFR: Addressing Genetic Counseling Dilemmas Using Evidence-Based Literature.” J Genet Couns.
[2]Moll S et al. (2015). “Homocysteine and MTHFR Mutations.” Circulation. 132(1):e6-9.
[3]Klerk M et al. (2002). “MTHFR 677C–>T polymorphism and risk of coronary heart disease: a meta-analysis.” JAMA. 288(16):2023-31.
[4]Clarke R et al. (2012). “Homocysteine and coronary heart disease: meta-analysis of MTHFR case-control studies, avoiding publication bias.” PLoS Med. 9(2):e1001177.
[5]Kumar P et al. (2015). “Methylenetetrahydrofolate reductase gene C677T polymorphism and breast cancer risk: Evidence for genetic susceptibility.” Meta Gene. 6:72-84.
[6]Teng Z et al. (2013). “The 677C>T () polymorphism in the MTHFR gene contributes to colorectal cancer risk: a meta-analysis based on 71 research studies.” PLoS One. 8(2):e55332.
[7]Den Heijer M et al. (2005). “Homocysteine, MTHFR and risk of venous thrombosis: a meta-analysis of published epidemiological studies.” J Thromb Haemost. 3(2):292-9.
[8]Gouveia LO et al. (2010). “MTHFR and the risk for cerebral venous thrombosis–a meta-analysis.” Thromb Res. 125(4):e153-8.
[9]Pu D et al. (2013). “Association between MTHFR gene polymorphisms and the risk of autism spectrum disorders: a meta-analysis.” Autism Res. 6(5):384-92.
[13]Crider KS et al. (2011). “Folic acid food fortification-its history, effect, concerns, and future directions.” Nutrients. 3(3):370-84. [14]Hickey SE et al. (2013). “ACMG Practice Guideline: lack of evidence for MTHFR polymorphism testing.” Genet Med. 15(2):153-6. [15]American College of Obstetricians and Gynecologists Women’s Health Care Physicians. (2013). “ACOG Practice Bulletin No. 138: Inherited thrombophilias in pregnancy.” Obstet Gynecol. 122(3):706-17. [16]Genetics Home Reference. “Homocystinuria.”