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  • Writer's pictureNancy Mullan, MD

Immunity and the MTHFR Gene Mutation

Updated: Jan 23, 2020

You can’t make all of the methyl groups you need when you have an MTHFR mutation, and you need methyl groups for strong immune function. You need them to make the DNA that your immune system uses to make its cells. It uses these cells to form complexes that defend your body from germs, foreign bodies or other substances that it perceives as non-self and a danger.

Your immune system makes cells that belong to two systems, a B cell system and a T cell system.

The B cell system makes antibodies, quick responders to a perceived insult. It is good to have a quick immune response, but it can get over the top. B cells are responsible for anaphylaxis, a sudden serious immune allergic response that at minimum gives you hives, but at worst can swell your airways, block your breathing and cause your death. This is the kind of allergic reaction that makes people carry epinephrine shots with them. B cell response is the cause of the peanut allergy that has made many schools a ‘no peanut zone’.

Among its other functions, the T cell system balances B cells and prevents the serious issues that B cells can cause. But T cells require more DNA formation than B cells, and if you lack methyl groups, your T cell formation will be impaired. You get a predominance of B cells, a lack of T cell regulation of them, and radical B cell effects. You get unbalanced, ineffective immune function.

If you underproduce methyl groups, you are subject to impaired DNA formation, slow wound healing, and impaired immunity. This is especially important in your gastrointestinal tract. Slow healing and impaired immunity there keeps you on a constant roller coaster of symptoms.

Your GI tract is your connecting point with the world outside of you. 70% of your immune system surrounds your GI tract. Balancing and keeping optimized all of the organisms that come into your body through your mouth is a central function of your immune system. But you need to get your body producing methyl groups before you can expect to have the kind of immune function that can handle the conditions in your gut.

This is why Dr. Amy Yasko’s protocol works on getting methyl group production in place first.

How long have you been struggling to get the organisms in your GI tract in balance? How long have you been pounding your body with antibiotics to try to control Lyme organisms?

If you have an MTHFR C677T mutation, you have suppressed immune function. If you have a homozygous (+/+) MTHFR mutation, you are especially vulnerable. The issue can be that you have too few methyl groups for optimal immune function. You need to address methyl group production. Then your body’s defenses can kick in and solve the problem.

What your doctor doesn’t know can hurt you. It can keep you on a treadmill of treatments, none of which turn the corner for you. If you have an MTHFR mutation, you will not respond to pharmaceuticals normally. Routine supplementation may not do it for you.

If you are succeeding with your current regimen, great! I am not thinking of you. I am thinking of those of you who have been sick over time. If your being sick just keeps dragging on, despite your having consulted many doctors and having done myriad treatments, you are the person I am talking to here.

You can’t just pretend a methyl group deficiency does not exist. Ignorance about the importance of methyl groups will keep you stuck also. Methyl groups are genetic regulators. They act in biologic systems that are central to life and function. You have to find out what you need to do to optimize your particular genetics. You need to know if your genetics incline you to have a methyl group deficiency.

You need to get this information from a doctor who knows about methylation. This is not routine information. It is as new as the completion of the human genome projection. Most doctors and other clinicians know little or nothing about methylation genetics. Just ask.

If you have an MTHFR mutation and you are not doing well, you can’t leave your treatment in the hands of someone who has no information about it. This mutation changes the way your body works and what you need to do to resolve the health issues you have.

I am an MTHFR specialist with years of experience working with this gene and the biochemical pathways surrounding it. I do not know another doctor with this kind of experience. I work with Dr. Amy Yasko who is the world expert in this area.

I have a free, downloadable ebook that you can opt in for at that gives you further detail about these issues. Click here to get your free ebook.

Have an Exploratory Conversation with me.

Get an Exploratory Conversation with me. In this 30 minute conversation with me, I will listen to the problems you have been having, look at the lab tests you email me, tell you what I think, and leave you feeling relieved. What I tell you will make sense, that there is a path forward, that you have a doctor who ‘gets it.’My fee is $129 for this conversation. It is quick and easy and does not involve becoming a patient. I can clarify your confusion and pull you out of the muddle. Contact me at and ask for this time with me. I look forward to being able to help, 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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