The MTHFR Gene: What You Need to Know Before Surgery

If you're planning on having surgery anytime soon, you may want to get tested for the MTHFR gene mutation. Roughly 40% of the population carries at least one copy of this common genetic variant, which can lead to issues when exposed to nitrous oxide anesthesia. Here's what you need to know.

What is MTHFR?

MTHFR stands for methylenetetrahydrofolate reductase. This enzyme plays a critical role in processing folate and regulating homocysteine levels in the body. The MTHFR gene provides instructions for making this enzyme.

People with certain mutations in the MTHFR gene have a reduced ability to process folate. This can lead to higher levels of homocysteine, an amino acid linked to heart disease, stroke, blood clots, pregnancy complications, and more when elevated.

The most common MTHFR mutation is called C677T. Those who inherit a copy of this mutation from each parent are considered “homozygous” and have more significant MTHFR deficiency. About 10-15% of people fall into this category.

MTHFR Mutations and Nitrous Oxide Risks

Nitrous oxide is one of the most widely used anesthetic gases. While generally considered very safe, it does carry risks for those with MTHFR mutations.

Nitrous oxide inactivates vitamin B12, which is another key player in homocysteine metabolism. This disables the body’s ability to process homocysteine efficiently.

In those with MTHFR mutations, nitrous oxide anesthesia can trigger a rapid rise in homocysteine levels. Studies show this effect can last up to several days after surgery as the gas leaves the body.

Elevated homocysteine is concerning because it causes oxidative stress and damage to blood vessels. This raises the risk of blood clots, heart attack, stroke and other cardiovascular complications during and following surgery.

People with two MTHFR gene mutations are considered at highest risk. However, anyone with a history of homocysteine issues, blood clots, heart problems or stroke should exercise caution with nitrous oxide.

Reducing Risks Before Surgery

Get tested. Ask your doctor for an MTHFR gene test to find out if you carry mutations. If so, share this information prior to surgery and discuss alternate anesthesia options.

Optimize B vitamins. Taking extra folate and vitamin B12 can help minimize homocysteine elevation from nitrous oxide. Work with your doctor to determine optimal dosing. Methylated forms like methylfolate are best absorbed.

Try alternate anesthesia. Local, regional or IV anesthesia avoids nitrous oxide exposure altogether. However, these may not be appropriate for all procedures. Discuss options with your anesthesiologist.

The MTHFR gene mutation is common, but its impacts on surgery can be avoided with proper testing and precautions. Being an informed patient is key to reducing risks. Talk to your doctor and don't be afraid to advocate for your needed care. With the right precautions, you can proceed confidently into surgery and beyond.