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  • Writer's pictureNancy Mullan, MD

MTHFR C677T Mutations and Anxiety

Updated: Jan 23, 2020

The MTHFR C677T mutation is an important cause of many health issues. It reduces the number of methyl groups your body can generate. You need an optimal number of methyl groups in your body to regulate the action of your genes, to form the cells that mediate your immune response, to keep the viruses in your body from making you sick, to make your nervous system function smoothly, and for many other very important functions.

When you have a C677T mutation, your immune function is compromised. Your body cannot make the cells that deal with infectious bacteria and other invaders. So you get infections, sometimes chronic infections, like Lyme disease or PANDAS from a reaction to the strep bacteria in your body. 

Most of your immune system is found in the lymph glands surrounding your gastrointestinal (GI) tract. 70% of your immune system is there. Your GI tract is your interface with the environment. All sorts of problem organisms come into your body through your mouth. Your immune system needs to be right there to deal with them.

But if you have an MTHFR C677T or an MTHFR 03 mutation, your production of immune cells is slow and infections in your GI tract can start and become chronic. This inevitably causes inflammation and leaky gut with all of the symptoms those conditions can cause.

But these organisms also release metabolic byproducts that get backed up in your liver, the organ that is supposed to remove them from your body. Liver overload is well known to cause anxiety. And you may experience irritability and depression in addition.

In order to deal with this, you have to treat the infection AND the underlying MTHFR issue. You have to both supplement methyl groups appropriately and support your body so it can make the methyl groups you need for immune function.

Otherwise you may be going from clinician to clinician because you can't get well. Some clinicians may be able to treat the symptoms temporarily, but they have to know biochemistry and genetics to address the underlying cause of the problem and move you toward genuine resolution of the issue.

Clinicians claim they are MTHFR experts all the time. Many doctors say that they treat MTHFR. They have fancy offices and upscale advertizing, but their knowledge about the several mutations is only very superficial. Can they tell you about the different impacts from MTHFR C677T, MTHFR A1298C and MTHFR 03? Often they cannot. They just lump all three mutations together. These mutations are quite different and have differing impacts. Don't get stuck with one of these clinicians. They do not have the background in molecular biology or genetics to get you safely through a treatment. They may hand you a formula with high dose methyl folate and/or methyl B12 that could put you through the roof.

Exactly how the MTHFR mutation will affect you and what supplements you need depends not only on whatever MTHFR mutations you have, but also on what mutations you have in the rest of the methyl group producing pathway. You may have to supplement other areas of that pathway before you can add high dose methyl groups without symptoms. And if your situation is complicated, you may not ever do well with a high dose methyl group donating formula. You will have to follow your biochemistry and start low dose methyl group supplementation.

I have a free, downloadable ebook at that gives you further detail about these issues. Click here to download.

If you have any questions about how your methylation mutations are being handled, you can get an Exploratory Conversation with me. It is a 30-minute conversation in which I will listen to your health issues, review your recent test results, and make recommendations about what  you should do. It will clear up any confusion you have about which direction is up, which supplements you should start first, how you should start them and what you can expect.  The fee for this service is $129. It is easy to set a time for one soon, and it can save you weeks or months of doing the wrong thing, lurching around in the dark with a clinician who isn’t that easy to reach or who doesn’t know that much about the genetics or molecular biology of MTHFR. Whether you have one or two mutations, you may be dealing with conditions in your body that are confusing and difficult to understand. You can cut through all of that and get clarifying input that gives you hope and moves you in the right direction. I look forward to being able to help you, Dr. Mullan

What people like you are saying about Dr. Mullan’s work:

I shudder at the thought of what my family would be like without Dr. Mullan. Thankfully, with her help, we have stopped my husband's chronic 30 year battle with kidney stones. He is no longer forming them and is stone free. My thyroid is now working normally, my body temperature is almost normal and my hair has grown back. My oldest daughter's Autism is in the process of being reversed and her hair pulling has stopped. The greatest blessing from our good health is the birth of my second daughter Ava, now one-year-old. At 50 years old I carried her to term. One of my doctors commented to me saying “ you are carrying this baby like a 22-year-old.” Yes, I am because of Dr. Mullan and working on my methylation pathway. One by one she is knocking off symptoms and bringing us back to health. The future is bright! Thank you, Dr. Mullan, for the work you do.


Wow. I feel great. Thank you for your help. It's amazing really. Like a light turned on. Curious to see what the next tests show. To ride this peak indefinitely is my goal. Ha. I have energy again. Yay!

Really grateful,


I am so relieved. My daughter is doing SO WELL since we started with you! We have been to so many doctors and tried so many things.Now I can start working on my own program with you....


So excellent! I literally learn something every single time and I get clarification on things that have been lingering in my mind… VB

You are giving people a huge gift by empowering them… It’s about helping the patient become their own healer by taking them to a higher level of consciousness… AL

Thank you so much, Dr. Mullan. Thank you so, so much for everything you do. MS

Wow! I have to tell you, this was such an uplifting session. It’s so nice to hear good news, especially about a child. Anxiety, OCD and a host of other mental/psychiatric symptoms have been a huge hurdle for me. So to hear this story of all those awful symptoms totally going away is such a bright light for me!!!! TR

Fantastic, caring, smart, savvy doc. I worked with Dr. Mullan for a couple of years to help MTHFR mutations and their associating expressions! To say the least! She's brilliant. At that time she had weekly calls for her patients - free - where we could ask questions and she would reply. What doctors do this? She does. She's also an animal lover and is right on about the way she practices medicine. I highly recommend her. In good health!


"Dr. Nancy Mullan is a beautiful person. She is an expert in her field and has helped our family so much. I am very grateful to her. She came highly recommended and I know why. I would recommend her and her website for information re: healing from a genetic point of view. Thank you, Dr. Mullan, for everything.”


"Dr.Mullan has helped me with issues that I have struggled with for years. She is knowledgable and practical. I would recommend her to others.”


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