Humans, by nature, are always looking for a new way to control the uncontrollable, and many now see genetic testing as the latest tool in an ever-expanding arsenal.
As you may remember from high school biology, our genes are essentially a blueprint for our cells. So, in theory, by examining our genes, we can predict what diseases we might get. We could also, in theory, change certain behavior if we test positive for a particular gene variation. In recent years, as the BRCA1 and BRCA2 genes have been linked with breast and ovarian cancer, the idea of genetic testing has become more popular.
Now, a mutation to the MTHFR gene is the latest to get attention. Several websites and products claim the gene is linked to various diseases, including cancer, blood clots, autism, and migraines. (The genetic company 23andMe says on their website, “It’s the most asked about gene.”)
But Dr. Lawrence Brody, Director of the Division of Genomics and Society at the National Human Genome Research Institute, says the studies are still inconclusive. “You will find people who swear that knowing this is very important and by knowing it you can tweak your diet and make yourself better. Those claims are really out of the realm of rigorous science, and I’ll be blunt about that,” Dr. Brody says.
“At surface level, it’s something that helps you move the folate in your diet to build things in your body,” Dr. Brody continues. “It’s also involved in producing methyl groups that are used in lots of different components of your body. It’s a pretty important pathway.”
There are two common mutations to the MTHFR gene, known as C677T and A1298C, and several small studies have linked these specific variations with disease — which is why some people are concerned. But Dr. Brody cautions that these studies have not been replicated. “The really big studies haven’t shown an association. In fact, most studies that have really been looked at thoroughly haven’t shown an association with anything. That’s a problem because people want this to be important.”
Brody believes the larger problem with preliminary testing is that people react with proactive interventions, but we still don’t know enough about whether or not these interventions are actually helpful. “We don’t yet have the evidence of whether there’s anything special you would do to prevent the disease based on your genotype compared to what you would do to prevent your disease anyway,” Dr. Brody says. “Knowing that you are a fraction of a percent increased risk probably doesn’t have utility at this point. That’s what’s still missing is what’s the intervention.”
In the meantime, Dr. Brody encourages us to stick with what we know does work: “Certainly exercise is a health-promoting thing. Keeping weight to a moderate level is a health promoting thing. Avoiding diets that are extreme in any one direction tends to promote health. For preventing specific things, preventing some cancers, not smoking is very, very important,” he says.