Should children be tested for MTHFR gene before vaccinations?

Dr. Keith Roach

Question: I keep hearing that I should have my children tested for the MTHFR gene before vaccinating them. What is the MTHFR gene? Does something about it lead to more vaccine injuries? — K.S.H.

Answer: The MTHFR gene codes for the enzyme methylenetetrahydrofolate reductase, an important enzyme in making the active form of folic acid.

About 10 to 15 percent of North Americans (higher in people of Hispanic or Italian descent) have a particular mutation in this gene (called the C677T, or “thermolabile” mutation). People with this mutation are at higher risk for low active folic acid, which can cause a high blood level of homocysteine. This, in turn, is associated with an increased risk of blood clots and coronary artery disease.

I should note that it isn’t having the gene that seems to put people at risk, but the presence of high levels of homocysteine. However, in a review of eight trials of people with high homocysteine levels who were treated with folic acid and other vitamins, there was no benefifit in terms of decreasing blood clots, heart disease, cancer or death, despite the effffffffffffectiveness of the supplements in lowering homocysteine levels. There is theoretical evidence that methylfolate may be more effffective than regular folic acid at reduc- ing homocysteine levels, but there still is no evidence that treatment reduces clinical risk.

There also is no evidence that people with MTHFR mutations are at higher risk during routine vaccination, and genetic testing for MTHFR mutations is currently not recommended by the American College of Medical Genetics and Genomics. I did fifind a paper showing that people with MTHFR gene mutations had a roughly doubled risk of fever, rash or enlarged lymph nodes from smallpox vaccine (which has a very high risk of adverse effffffffffffects relative to routine child or adult immunizations).

I don’t recommend testing.