“What is MTHFR?”

When people ask, ‘What is MTHFR?’, do they mean what is the MTHFR gene or do they mean what is the MTHFR enzyme?

In this article, I am going to provide you the basics of the MTHFR gene.

  • What does MTHFR stand for?
  • Is MTHFR a gene or an enzyme?
  • What other terms are used for MTHFR?
  • Where is the MTHFR gene found?
  • How big is the MTHFR gene?
  • What is the function of the MTHFR gene?
  • Why is the MTHFR gene important?
  • How much of the MTHFR gene gets mutated?
  • Common mutations of the MTHFR gene

What does MTHFR stand for?

MTHFR stands for the methylenetetrahydrofolate reductase gene (methyl-ene-tetra-hydro-folate-reductase).

Is MTHFR a gene or an enzyme?

For some reason, scientists thought they should name the gene MTHFR and also name the enzyme MTHFR. This is confusing and causes confusion especially if MTHFR is not labeled as MTHFR gene or MTHFR enzyme. Think of it this way: a healthy non-mutated MTHFR gene is supposed to produce plenty highly functioning MTHFR enzyme.

What other terms are used for MTHFR?

NADPH is 5,10-methylenetetrahydrofolate reductase. The MTHFR enzyme, made by the MTHFR gene, converts 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate.

Where is the MTHFR gene found?

The MTHFR gene is found on the short arms of Chromosome 1. There are two short arms of chromosome 1. Why? Because one short arm of chromosome 1 comes from the mother and the second copy comes from the father.

How big is the MTHFR gene?

The MTHFR gene is made up of 20,373 base pairs. A base pair contains two DNA nucleotides. A DNA nucleotide is made up of pyrimidines. The MTHFR enzyme actually helps produce pyrimidines – but that is getting ahead of ourselves.

What is function of the MTHFR gene?

The function of the MTHFR gene is simply to produce the MTHFR enzyme. However, if the MTHFR gene is mutated, the enzyme produced is not entirely correct.

Why is the MTHFR gene important?

The MTHFR gene is responsible for making a functional MTHFR enzyme. If the MTHFR gene is slightly altered (mutated), the MTHFR enzyme’s shape becomes distorted. Enzyme function depends a lot on shape. It is similar to the grooves on a key. If the grooves on a key are slightly different than the lock, the key may fit and turn the lock a little but it does not unlock the door.

The genetic code of the MTHFR enzyme must be perfect in order for it to function properly. A dysfunctional MTHFR enzyme may lead to a slew of health problems.

How much of the MTHFR gene gets mutated?

In heterozygous MTHFR mutations, only 0.000098% of the MTHFR gene is mutated. In homozygous MTHFR mutations, the value is basically the same.

This means there is just 1 mistake for a heterozygous MTHFR gene mutation out of 20,373 steps done properly.

There are 20,373 base pairs making up the MTHFR gene on each chromosome. Remember one chromosome comes from the father and one comes from the mother.

What are the most common MTHFR gene mutations?

The most common MTHFR gene mutations are found at position 677 and/or position 1298 on the MTHFR gene.
At position 677 of the MTHFR gene, a Cytosine is what is supposed to be found there. When mutated, the Cytosine gets replaced with a Thymine.

At position 1298 of the MTHFR gene, an Adenine is what is supposed to be found there. When mutated, the Adenine gets replaced with a Cytosine.[1]

Researchers present MTHFR mutations most commonly like this:

  • MTHFR 677CC = a normal MTHFR gene
  • MTHFR 677CT = a heterozygous mutation which is one mutation
  • MTHFR 677TT = a homozygous mutation which is two mutations
  • MTHFR 1298AA = a normal MTHFR gene
  • MTHFR 1298AC = a heterozygous mutation which is one mutation
  • MTHFR 1298CC = a homozygous mutation which is two mutations
  • MTHFR 677CT + MTHFR 1298AC = a compound heterozygous mutation which is one mutation from two different parts of the gene

Long Term Solution for your MTHFR Mutation

Now that you realize what MTHFR is and how it may be actually causing you issues, I’d really like to see you get on a full program.

Reading my book, Dirty Genes, will help you immensely.

You’ll learn about MTHFR and how to use methylfolate in depth, yes, but you’ll learn WAY more than that.

Empower yourself and take action the right way.

Dirty Genes is the guide you’ve been looking for.

It continues to be a bestseller month after month for good reason.

Dirty Genes book by Dr. Ben Lynch

You’ll see why once you pick it up and start reading 😉

Don’t like reading books? Want to get more in depth and see how it all ties together?
Get access to the Dirty Genes Course where I discuss how food, lifestyle, environment, mindset and genetics are influencing how you’re feeling – and how to deal with it all.

The Dirty Genes Course is where I bring in a lot of published research, translate it and make it actionable for you. It’s an extension of the book, Dirty Genes. There is a lot of science, biochemistry and actual examples of how to use this stuff in your daily life.

Is it going to be over your head in terms of difficulty?

Absolutely not.

You’ll learn a ton and you’ll be amazed how easy it is to implement what you learn.
Any comments or questions relating to what the MTHFR gene is, please post a comment below.

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Anuj S.
10 years ago

I am heterozygous CT genotype. What does this mean?
My doctor wants me to take Deplin 15 and methylcobalamin subcutaneous injections.
I am dealing with neuropathy, insomnia, fatigue and depression.

10 years ago

I am having trouble understanding what, exactly, the mutations are. I have AA at C677T, and TT at A1298C.

In a user thread on 23andme, C677T/AA is flagged as being troublesome; A1298C/TT is not.

“The Name Game” from the page at says that there are two variations at position 677, C and T (hence C677T). Likewise at 1298, A and C. So how do I have As at 677 and Ts at 1298? And why is only one of those a problem?

Help! I am so confused…

10 years ago
Reply to  Shannon


While 23andme gives AA for C677T, as does Yasko, Promethease gives TT
While 23andme gives TT for A1298C, as does Yasko, Promethease gives AA

All three flag that 677 as a problem. All three call the 1298 result good.

All three are looking at the same raw data.

Does Promethease invert the call (A->T, C->G, etc) to give their result? Which result should I give a physician if asked about it?

10 years ago
Reply to  Shannon

I have exactly the same alleles at C677T and A1298C and have been confused by exactly the same thing!

Must be a simple explanation… anyone?

9 years ago
Reply to  mark

Simple explanation: Bases in DNA are paired. So A pairs with T and C pairs with G.

The result you are getting may be due to which strand of the DNA was sequenced through the 677 and 1298 sites in your test. The forwards strand would have C (or T if you have the mutation) while the reverse strand should have G (or A if you have the mutation.

[…] different health/lifestyle issues that can contribute to Hashimoto’s, one of them being the MTHFR gene mutation. This was one that I hadn’t really looked at as I thought it would not really factor in my […]

10 years ago

Dear Dr. Stein,

I was recently tested and have the A1298C Homozygous mutation. My sister has the compound mutation. My son has the compound mutation. How would I have two copies of the mutated gene and my sister only have one of the 1298 mutation? Could my test be wrong since my son has both as well?

Pamela Sage
7 years ago
Reply to  Patti

Neither mutation is that rare. Barring spontaneous mutations, both of your parents would carry the 1298 mutation, but one or both would have been heterozygous for the 1298 mutation. One or both of your parents would also have been heterozygous for the C677. You inherited the mutated 1298 from both parents. Your sister inherited a mutated 1298 from one parent, while inheriting the normal copy from the other parent. If I understand you correctly, you do not have a C677 mutation. If both of your parents were heterozygous at C677, you and your sister each had a 50% chance of inheriting the mutated form or only 25% if only one parent carried one mutated C677. If you can remember your Mendelian genetics from grade school, you can calculate the probabilities for different outcomes. The cards of the deck are reshuffled for each child. Now you say you received mutated 1298 from each parent but no C677 mutation. You definitely passed on a mutated 1298 to your son. For your son to be compound, he then received a mutated C677 from his father. As I said, sizable minorities of the population carry one of the other of the mutations and are blissfully unaware of it. Normal copies mask most of the ill effects except for those who are homozygous for one of the mutations or get the compound mutation, which greatly inhibits methylation.

10 years ago

I’m confused my 23andMe report says I have the following:

MTHFR C677T rs1801133 A AA +/+

The “+/+” is in red. I couldn’t match this to your table above. How many mutations am I?

10 years ago

Here’s more information:
dbSNP Orientation: Minus
dbSNP Genotype: TT
Also, would there be any benefit to getting the following additional test from Quest Diagnostics?
Methylenetetrahydrofolate Reductase (MTHFR), DNA Mutation Analysis: Quest Test Code: 17911
Or, do I have everything I need from my 23andMe test?

10 years ago

Dr. Ben:
Just a simple (and maybe not so simple to answer) question:
What kinds of physical problems does this mutation cause?
I have a friend who is being tested for this because she suffers from much fatigue, which could be related to thyroid or adrenal issues. Could you elaborate a bit on what impact this mutation has on the body? Thanks!

10 years ago
Reply to  Dr. Ben Lynch

thank you

9 years ago

Hello, and thank you for making yourself available to answer questions.

1. My tests have thrown me a curve ball. They came back as homozygous for C677T and Heterozygous for A1289C.

My doctor hasn’t seen this before, and none of the information I can find mentions it either. Is it as rare as it seems? As far as getting educated and for advice, should I just be looking at information on compound MTHFR mutation?

2. We have just about every condition that could be associated with MTHFR mutation in my family, but I only recently heard about it and I am the first one to have been tested. Am I correct to understand that both of my parents must have the 6776 mutation, and at least one the 1289? So should my Aunts and Uncles should also be going for testing as well as their kids?

9 years ago

Julia, from what I understand 44% of the population has hetro C677T and 12% has A1289. I have C677T from my mom and A1289 from my dad…that makes me compound Hetero…I am not sure how many people have homo C677T, but if 44% of the population has at least one copy of it, you would think that it is more common than one would think…but to be homo C677T and hetero A1289C … that is interesting … do you have clotting issues, fertility issues … I know you said your family has almost all of the symptoms … I only ask because I have fertility issues and that is how I found out … have they checked you for clotting disorders … that seems to be the most dangerous one that comes to my mind … I am sure one of the admins can make heads or tails of this and also tell me if my info is correct. I haven’t received feedback on this forum from an admin…I am going back into fertility treatment so any info about any of your questions, mine or anyone else’s would be great…hint hint…don’t panic … read this site and add methylfolate and methyl B12 and watch out for pain associated with opening your methyl pathways…if that happens then take niacin…I didn’t know that when I did it…good luck 🙂

9 years ago
Reply to  Sarah

Hi Sarah, thank you for taking the time to reply.
Due to having been sick with ‘fibromyalgia’ most of my life, and seeing that my relatives were all sick I felt that my kids chances of being healthy were slim to none, so haven’t tried to have children. I have always had problems with my menstrual cycle and hormonally fit the profile of PCOS although ultrasounds have only shown a couple of minor cysts.

Fertility was an issue for my mum, the doctors told her that it was a miracle she ever carried a child, and that she had four of us was astounding. She had to have a hysterectomy in her early 30’s due to hemorrhaging causing constant anemia. Mum has problems with clots and has thrombophlebitis, vein inflammation. My sister also has problems with clots, she’s currently dealing with some in her lungs. My doctor want’s me to have scans done to check my lungs and brain for issues due to shortness of breath and neurological symptoms, so I guess that should get covered. A test for von-willebrands has been ordered, but I’m not sure that is the right sort of blood test.

9 years ago
Reply to  Sarah

Hi Sarah & Julia,
I’ve been looking for answers for a long time. I am compound hetero as well. I don’t know which copy came from which parent.
I’m worried about my son who has not been tested. He has shaky hands all the time. That scares me and no one knows why.
I’ve had problems with clots – had to had veins stripped out of my leg. Was told I have PCOS. I have shortness of breath. Had cervical cancer. Suffer with anxiety along with depression. I am in pain all the time, muscle pain, headaches ALL the name a few. Sister had an ablation because was causing anemia & she had fertility issues as well. Father passed of brain cancer.
What are you taking exactly and how has it helped?

9 years ago
Reply to  Sarah

I don’t think anyone AKA – admin… Reply to anyone on here. I think he just try to sells his vitamins or something.

Also wanted to tell you.. My sister did have fertility issues. Took her awhile to have her first child without any help from the doctors, she did want more children and wasn’t happening so she did do fertility and she got pregnant with twin girls. She has 3 healthy kiddos!

I have one child but that’s all I tried for and I wasn’t trying ( if you know what I mean )

I’ve read a lot about PCOS and with it is fertility issues. My doctor treats PCOS and his office is filled with pictures of babies who when prescribed Metformin – for some reason, ( I’m no doctor ) they get pregnant.

Just thought I would mention this.

Annmari Cooper
9 years ago

I have just received some blood work back, as my PCP is trying to figure out why I am so sick and having daily terrible headaches among other things. The lab results came back saying” Two mutations (C677Tand A1298C) identified. I have not yet been contacted back from my doctor as to what that means if anything for me. I was just researching on my own to see if I could figure anything out, however, I am just now more confused.


9 years ago

I did the 23andMe testing and have AG for C677T and GT for A1298C. I believe this means I have the mutation, although I am still unclear about most of this. Can you describe in layman terms what this means for me? Many thanks.

9 years ago

Hi I was just told I have the MTHFR ( A1298C) so I am guessing from reading on here I have the Heterozygous. Is that right? I do not understand all of this and I am so overwhelmed by this. My Dr. put me on a medicine food called Podiapn because I can not afford the L-methylfolate. I am disabled and Medicare nor Medicaid will pay for this. Is this safe to be on?? I met a person who has the same mutation and she has never heard of Podiapn and she said on your website you don’t recommend presciptions for this. Any info you can give me would help me so much. I know I have more questions but was wondering about this. I go to my Dr this Friday June 20,2014 and will try to get more info from her. Thank you for an help you can provide…..

[…] the root cause(s) of my problems. It turns out I also have Pyrrole Disorder and am positive for MTHFR. Oh yes – and this year I threw in some periodontal surgery for good […]

Robin McStay
9 years ago

Hi Dr. Ben,

My son is eight years old and has a complex medical history.

He was apparently normal until he was approximately two years old, then began having some “autistic like behaviors”, absence seizures, gelastic seizures, and eventually a full range of drop seizures, status, and severe cognitive loss. He was first diagnosed with Lennox Gastaut Syndrome, but ultimately diagnosed at Lucille Packard with a Hypothalamic Hamartoma.

The hamartoma was resected at Barrow Neurological Institute in June 2010, and he has been seizure free since that time. His cognitive decline stopped and he has made many strong advances, but he has not recovered.

He has several comorbid symptoms that I wonder if the cound be attributed to MTHFR. he has a lisch nodule in his eye (as I understand, NF1 has been definitively ruled out). He is very large in stature, above the very top of the growth chart for both height and weight, though his testosterone levels have not yet started to increase. His appetite is that of a grown adult, but he does not accumulate extra body fat. He is not diabetic or hypertensive. His sweat smells VERY STRONGLY OF AMMONIA.

In addition to cognitive impairment, he also has problems with emotional dysregulation, and he has certain OCD and ADD/ADHD and anxiety symptoms.

Thank you for your opinions on this matter.

9 years ago

my Spectracell test says A1298C Heterozygous
not AC or CC

What’s this?

Lauri Ongley
9 years ago

I recently found out that I have mthfr C677T and A1298C so I know I passed it on to my daughters. My youngest was told to take folate and did so for about 2 years. I know it wasn’t the methyl form of folate. Could it have harmed her to take it? Thank you for your help.

9 years ago
Reply to  Lauri Ongley

I am compound heterozygous.
From my understanding is that you get one copy from mom or dad..
Doesn’t exactly mean they will have the same mutation , if any.

My sons came back compound homozygous and from what that doctor told me he got one copy from me, one copy from his father.

Someone please correct me if I am wrong.

I have been told ridiculous stuff from misinformed doctors, what you can do is read Dr. Lynch’s information and YouTube videos. I have received no help from doctors in my area.

I recently called a doctor and asked flat out, plain and simple if he could help me as I absolutely feel a lot of what I am going through has a lot to do with MTHFR and I want that route deeply explored by a qualified physician.
I made tons of calls and finally this doctor said yes. A week later I’m sitting in his office and he is telling me my two copies that have me positive actually cancel each other out, like a math equation, which makes me normal after all.
Well. Well. Well. I’ve never heard of this before I say !
I was his last patient of the day. Just him and I. He had no intention of helping me or do anything for me.
I started crying in his office at which point he told me it was time for me to go.
He billed my insurance for 600.00 for about 7 minutes of his useless time.
I was so upset I could hardly drive home.
I’ve been trying to find a doctor for two years.

All I can do is hope and pray a doctor like Dr. Lynch will come along , a doctor who actually cares.

I mean no disrespect to the doctors out there that do care.

9 years ago

Dr. Ben,
After a miscarriage, and almost dying from blood cots after my second pregnancy and my half sister’s son having a stroke at the age of two. Our family began genetic testing. My sister, my nephew, my niece, my mother, and one son all have Factor IV Leiden and MTHFR. I also have another child who was only diagnosed with the MTHFR. I have been prescribed Foltx to take daily. Neither of my children have been prescribed any type of daily regimen. During pregnancies, I had to see a high risk OB along with my regular OB and take Lovenox injections every 12 hours in my stomach, towards the end of pregnancy, they switched me to Heparin injections every six hours. I had twins that arrived 8 weeks early, but are healthy. One twin did not inherit either, and the other inherited both. Then I had another pregnancy, did the same regimen, and he came about 5 weeks early, he is healthy, but got the MTHFR mutation. How important is if for me to know the details of our mutations? I was not given that specific information, but I was diagnosed over 10 years ago and VERY FEW medical providers had even heard of it. To this day, it’s getting better, but most look at me like “huh?”. I would appreciate any information you can offer.

Thank you,

talia hewitt
9 years ago

Hi iv had 1 stillbornhe was 41+1 weeks 2 misscarages 1 complete the other I had the D&C opp I have this gene and also my partner I am on B6 B12 B1 and also megafol5 and just need help as I want a baby and its getting me down as its all I ever wanted for the last 3 years
Thank you

9 years ago
Reply to  talia hewitt

Hi Talia. I am so sorry for your loss. I would like to recommend that you read my book, Brighton Baby. It is available at It is over 1,000 pages long and goes through preconception and provides lots of great insights for how to prepare your body for a healthy pregnancy. Wishing you great success and love.
Dr. Dittman

9 years ago


About 3 years ago randomly one night i woke up with what i thought was a UTI as i have had many in the past. I went to several different doctors and a UTI infection was no where to be found in my urine sample. Finally after many doctor and ER trips i was referred to a Urologist. They diagnosed me with IC. At about that same time i randomly woke up in the middle of the night with the worst cramp in my calf that i have ever had. No warning signs earlier in the day, nothing. The cramps and the bladder problems have not stopped ever since that day. I CONSTANTLY have twitching in my legs and feet and cramp to the point that i cannot move or walk. I have had to be carried out of stores, stuck in positions that i cannot move, etc because the cramps are so intense. I had several nerve conduction tests done, all coming back with the result of “over active nerves” but no further diagnosis. I have been turned down by doctor after doctor after doctor because while my symptoms are there, no one knows why this is happening. I also get tingling in my feet occasionally. I have had MIR’s done on my spine and brain and they all came back normal. I have had labs done to test for low vitamin levels, liver tests, etc. My liver test came back a little abnormal and they also have no answers for that. I have been on 900mg 3x a day of Gabapentin and also 20mg of Baclofen 3x a day for the last 2 or so years. My urologist is the only doctor that seems to care, and is trying to help me figure out my leg cramp/twitching issue even though that is not necessarily in her field. She recommended me to your site, and i am hoping you might have some answers. I have not had the blood work done for the MTHFR that i see most people talking about on here. I also have severe anxiety and have addiction issues 4.5 years ago. I am 100% now and do not drink or anything else. My urologist wanted to start doing more blood work since my symptoms have suddenly started to get worse. Do you think getting tested for MTHFR is something that i should do based off of my symptoms? Desperatly looking for a doctor that is willing to help and point me in some sort of direction to figure this all out. I am in constant pain and cannot do certain activites that i was once able to do. 25 year old female. 1 ectopic pregnancy 4 years ago before any of my other symptoms started to occur. My right side falopian tube has been removed. Please, any suggestions would be greatly appreciated.

9 years ago
Reply to  Alicen

Hello Alicen,

Not knowing much about your case, I would suggest looking into having a hair mineral analysis done and interpreted by an experienced practitioner. I would guess that your calcium-mineral ratio is off and that you have a copper-zinc imbalance. This can affect the nervous system and your muscle relaxation response (among other things). It would at least give you a good first map that could lead to other things. Also, have you been tested for heavy metal toxicity, in particular aluminum and mercury? Quicksilver Scientific has a Mercury Tri-Test which is able to better assess mercury burden through fish, vaccines, mercury amalgams, and other environmental exposures. This can profoundly affect the nervous system and trigger an underlying copper-estrogen-candida imbalance.

9 years ago

I have tested positive for mthfr because i was anemic and my b levels were past 2000. i am now on methylated b vitamins..

9 years ago

Hi Ben,
I got told I have heterozygous C677T. I have Spina Bifida and need to take 5mg folic acid. I am now on methyl form compound vitamins.
do I need to avoid all B vitamins and all supplements that have them (even if they are in there in small amounts)? And take 5mg folinic acid instead of Megafol?

7 years ago
Reply to  Penelope

Just commenting since I’m fascinated by this post.
I’m new to all this and had my genetic testing through Ancestry, and then put the raw data through Promethease. I have the heterozygous C677T (rs1801133(C;T) AND spina bifida! Fascinating to see how genetics plays a factor.

9 years ago

Hi, I’m hoping someone here can clear this up for me. Hi, Dr. Ben! I hope you get this. Does the finding of rs1801131 C;C indicate a result of being homozygous for A1298C? I recently found out that my son is homozygous for A1298C, but is it CC or AA? My result was rs1801131 A;C, which I know is heterozygous. My mother is rs1801131 A;A. Which one is “normal,” and which one is homozygous, CC or AA? Thanks so much to anyone who can help me!

9 years ago

I know very little about MTHFR. But i got tested because it runs in the family. My results were 677C>T Homozygous on BOTH chromosomes AND 1298A>C Heterozygous on one. Is it possible to have 3 mutations? or is this a mistake? And what does that mean? Where can i find information on this and what supplements should i be taking?

Dr. Aron
8 years ago
Reply to  Tammie

Hi Tammie – Yes. This is possible to have this result. What this means is that you may be more susceptible to methylation dysfunction. Factors like diet, lifestyle, and stress are important factors in how you feel. A clean diet and healthy lifestyle may be all you need. Please see the Starting Protocol where Dr. Ben goes into detail about the diet and lifestyle recommendations for anyone with MTHFR gene mutations:

Hope this helps.

-Dr. Aron

8 years ago

Hi Dr Ben,

I’ve just had the gene testing done and the results are –

MTHFR (CT77T) Homozygous wildtype CC

MTHFR (A1298C) Homozygous variant genotype CC

Can you please help me interpret what that means?

8 years ago
Reply to  Martyns

Sorry a correction-

*MTHFR (C677T) Homozygous wildtype CC

MTHFR (A1298C) Homozygous variant genotype CC

Dr. Aron
8 years ago
Reply to  Martyns

Hi Martyns – MTHFR (C677T) Homozygous wild type CC is 2 copies of the normal variant in the population, so no mutation. MTHFR (A1298C) homozygous variant genotype CC is two mutations at this gene location.

From one of Dr. Ben’s previous comments:

What you have are two copies of the A1298C MTHFR mutation which means you have a defective BH4 pathway and this can lead to a multitude of symptoms.

Neurological, mental, muscular and sensitivity to chemicals are common for this mutation.

You do have a chance to be well or at least much better if you begin to address the A1298C mutation.

Hope this helps!

8 years ago

Thank you very much, that does help a lot.

8 years ago

I’m not sure if you could helps me with this but along side the gene test i had some other blood work done.

Things that were of note were my zinc, magnesium and manganese, vitamin C and Vitamin E, essential fatty acids (EPA, DHA, and Lauric acid).

What was high was my B12 and also my levels of SOD. Are either of these a concern?

When I had my hair mineral analysis down a couple of years back my lead and mercury levels were high. Could heavy metals be responsible for the high levels of SOD combined with the depletion of antioxidants?

I will be getting my hair retested soon to see where I stand with that but need to let me hair grow out a bit first.

I also had various gut issues in the past which I have now managed to get under control through manipulating my diet and ensuring i include a high intake of probiotic foods.

Now obviously i’ve upped my intake of the low nutrients to help address this and will be looking to include a methalated folate supplement.

Overall my lifestyle is very good, I eat well, sleep well and manage my stress pretty well too. Bi polar disorder runs in my family but so far i’ve only had one ‘wobble’ a few years back during a particularly stressful period at work.

8 years ago

Can you be homozygous for both strains of the mutation? The C677t and the A1298?

Kirsten Norgaard
8 years ago

Please help! I tested positive for mthfr and my results say C665t LLS heterozygous…

Helen hallett
6 years ago

Please help. I had a test done and they told me I have MTHFR c.665C>T. Can you help me understand this. The doctors said I have to have a blood test for folic acid. I have hashimotos and fibromyalgia,
arthritis of the nee and hands, lost sight in one side of my eye which now returned. Please help

8 years ago

Hi Dr. Ben,

When I was pregnant with my first I had genetic testing done, I am compound heterozygous- C677T/A1298C. My daughter ended up being fine and I forgot all about it. My doctors never seemed concerned or gave me information. We are now trying for our second and have had one miscarriage and haven’t had any other luck after a year. How much would this be caused by my diagnosis and what can I do to counteract it?
Thank you!

8 years ago
Reply to  Kelly

I should mention my husband is also a carrier C677T.

Dr. Aron
8 years ago
Reply to  Kelly

Kelly – Dr. Ben has written a general approach to prenatal supplementation here. This should give you a good place to start with some strategies to discuss with your doctor. Best of luck!

8 years ago

I have 2 copies of 677t and one copy of 1298 what does that make me

Maureen Harris
8 years ago

hello, Dr Ben I’m from South Australia and I have MTHFR Homozygous CC mutation and have all symptoms of Vit B 12 deficiency particularly concerning is the brain fog weakness & fatigue, muscle pain & wasting, & burning, twitching. Dr gave me a B 12 injection of 1 ml hydroxocobalamin a week ago, which gave me headaches and bad gut cramps, my head feels a bit clearer but my eyes are still sore. Previously I had Methy Max which has Cyanocobalamin & calcium folinate which should have suited me but it made me feel worse. (I am not on calcium folinate at present as I stopped as my symptoms did not change as the Vit B12 (cyancobalamin )treatment I had 8 years ago did not reverse the symptoms.)
I’ve been struggling with chronic fatigue since then.
My Dr wants me to start on “Seeking Health” Active B12 hydroxocobalamin Lozenges.
I am wondering if the Active B12 Lozenge with L-5-MTHF, would be more suitable for me, than the Active B12 hydroxocobalamin? Is methylfolate easy to be absorbed when I was told 10 years ago I needed to be on Calcium folinate for life as I could not absorb folic acid.

In summary I really would like advise on which form of Vit B12 lozenge would be best for the double mutation I have. Or do I need to experiment?

Kind regards,
Maureen Harris

cathy nutting
8 years ago

Dr. Ben, I was tested by HealthDiagnostic LaboratoryInc a few years ago. My result “this patient has the normal or wild-type genotype for the MTHFR C677T (C/C) polymorphism and is heterozygous for MTHFR A1298C (A/C). The A1298C A/C genotype may result in reduced activity of MTHFR, potentially leading to dimished production of L-methylfolate, the active form of folate. Reduced levels of L-methyfolate lead to decreased production of neurotransmitters, reduced conversion of homocysteined to methionine, and reduced SAMe concentrations. CNS neurochemical deficiency along with buildup of homocysteine and decreased availability of methyl groups from SAMe may increase an individual’s risk for developing cardiovascular disease. Additionally, this may predispose an individual to certain psychiatric disorders and/or memory and attention deficits. Patients with the MTHFR A1298C polymorphism may consider supplementaion with the active L-methylfolate in combination with Vitamin B12. Increased homocysteine levels may reflect of conditions.” I have been healthy (I am 58 years old and delivered 4 healthy babies and never had a miscarriage) My only health issue is insomnia which is very severe. It is normal for me to sleep 1-3 hours or not at all. I have been to multiple sleep specialists and have been on lots of different meds. I am now seeing a naturopathic nutritionist who said this gene mutation could be the root cause of my severe insomnia…is this possible and is there anything to do about it? Thank you very much, CAthy

8 years ago

Hi dr.Ben.
Could you please help me with this?
I am 32 years old and had 3 miscarriages , my blood result is homozygous CC for C667t and homozygous AA for A1298C. What does this mean? Can this mthfr result be a problem for pregnancy and if so how can this be treated?

Dr. Aron
8 years ago
Reply to  Hanna

Hanna – Please start by reading Dr. Ben’s article on Prenatal Supplementation. It’s a general guideline, so please consult your doctor if you have specific questions.

Cheryl Vasiliou
8 years ago

Makes sense for most part so far!

Stephanie Relly
8 years ago

Hello, I have questions regarding my labs. My doctor had these done and mentioned that I have the mutation, but I am pretty confused. This is what the lab result looked like:
677C>T Wild
I have a lot of pain in my legs among other issues. I am desperate to see if this could be part of the problem. I also just feel “toxic” inside, if that makes sense? Thank you. I am pretty discouraged. Also, my daughter has extreme pain all of the time, was just diagnosed with Hashi Motos and Lymes, but I am wondering if this could be part of her problem?

Dr. Aron
8 years ago

Stephanie – MTHFR is one part of the puzzle and could be related to these issues. Hashimoto’s and Lyme can definitely be a cause of your daughter’s pain. Please reach out to a doctor on the Physician Directory. You will want to find someone who is trained to work with Lyme. With proper Lyme treatment and focus on diet and lifestyle, there is hope that she will get better. Take a look at the Basic Protocol to get an idea of Dr. Lynch’s general approach. Wishing you all the best.

8 years ago

Hi dr.
I have recently had this test done to check to see if my antidepressants were a correct match. I’ve been on the same ones for years but still not satisfying the anxiety side. I’ve done therapy for years and taken anxiety classes. While I’m able to run a company and succeed in many aspects I still can’t quite conquer this one. Can you explain what these 2 possibly mean. My genotype came back c/c and a/c reduced activity.

8 years ago

I was wondering if you could help me. I live in Korea and I recently got tested for this mutation.
I have the following on my lab test result sheet.
C677T – Heterozygote CT Wild type and 1MTHFR gene (A1298C) Heterozygote wild type.
I have been attempting pregnancy for 3.5 years and having never succeeded it is difficult to know if this would have been a problem.
However, my question is regarding now. My RE has prescribed me an extra strong daily dose of folic acid, my understanding is that actually this may not be helpful to me.
Please can you advise what I should be taking prior to my next round of ivf, anything to avoid etc. It would be really helpful to understand what these results mean for me,
Many thanks

Dr. Aron
8 years ago
Reply to  Stella

Stella – Please start by reading these articles on the Basic Protocol and prenatal supplementation. Of course, consult your physician or find one who can point you in the right direction.

8 years ago

After having Boston Heart Panel and SpectraCell Lab Micronutrient testing in November, was diagnosed with 677 C/T 1298 A/C so just starting the journey to understand all this. What does this mean for me exactly? Also have functional deficiency for copper and 4 border line deficiencies in choline,manganese chromium and zinc. Homocystine has been normal pretty much. First pregnancy was a miscarriage, then two health pregnancies although for one I had gestational diabetes. Did not become Type 2 diabetic until a year ago. I am 64. Conditions that have been problematic and for which I have sought treatment over the past few years are metabolic syndrome, depression, hypothyroid, migraines, Type2 diabetes, sleep apena and recently experiencing a lot of insomnia and disruption in normal sleep. Not a lot of energy lately. Huge history of cancer in my dad’s family. Have testing scheduled for Lynch Syndrome in Feb. Treatment plan includes paleo diet, a few more supplements added to what I have been taking, more exercise. Things I have already been trying to do over the last few years with varying success. Overwhelmed and confused with the information out there on the topic and wish more of it were in plain English. Not fully clear on exactly what it all means.

8 years ago


I am MTHFR C677T and A1298C and i have a really high B6 reading at the moment of 2250 (range 20-190)
I do take gaba x 2 or 3 a day that has 2mg per pill so i take say 6mg pd which i think is more than i should.
I am just trying to understand the link ???? (all a bit new to me)
I need to get heavy metal tests done do you suggest blood or other? thanks Sara

8 years ago

Is it possible to be homozygous 677/1298?
All the info on MTHFR mutations that i see has only heterozygous 677/1298 as a possibility. Is it not possible to have the 677 and 1298 mutation on the same half of he gene, with 2 copies making homozygous 677 and 1298?

8 years ago

My girlfriend was just diagnosed with a methylfolate mutation. Her lab results list it as a1298c. So would that be the heterozygous mutation listed above as 1298ac?

8 years ago

Hi, I just found out that my step daughter has the MTHFR heterozygous C677t1 A1298C. I have a 1 year old son should I have him tested?

Dr. Aron
8 years ago
Reply to  Nicole

Nicole – You may want to run the test if there is a clear reason to run it. If you or your son’s father have a significant medical history or your son has congenital health issues, it might be a good information to have on hand. Knowing his MTHFR status is one piece of data that has to be incorporated into the whole picture.

Brittany Gray
8 years ago

Hello I am in need of help. My 7 year old son has been through the ringer and we have been searching for answers. He had some genetic testing and I am having difficulty reading/understanding all the info all 3 Drs are giving me different and even conflicting information. Under MTHFR it reads ” c667t, ct”then “a1298c, ac”then “intermediate activity” his labs show an excessive amout of vit b12 (2000 which is more than 1000 over range) and folate 20.0 (it says less than or equal to 7.3 is where he should be) One Dr says there is no problem with it, another seems worried about it and repeatedly asked if I gave him folate supplements. The other had no idea what I was referring to so he looked it up on his phone and said it would be depleted not elevated if there was anything to worry about. I have a 2 year old neice that has been having terrible year (ie having seizures ect) and the special Dr they take her to said this mutation played a large part in that. I am currently trying to find ANOTHER dr for my son but could use some guidance and advice in the meantime.

Dr. Aron
8 years ago
Reply to  Brittany Gray

Brittany – All of this can be difficult to understand for everyone involved. You can find doctors who have completed training with Dr. Lynch here:

8 years ago

NADPH is 5,10-methylenetetrahydrofolate reductase.

No it isn’t.

8 years ago

DNA nucleotide is made up of pyrimidines

No it isn’t. A nucleotide consists of a sugar, a phosphate group and a base. The base can be a purine or a pyramidine.

Rebecca London
8 years ago

In the information given from above in the “What is MTHFR?”, MTHFR C677T is not listed under “What are the most common MTHFR gene mutations?”. Why is that please?

Researchers present MTHFR mutations most commonly like this:

MTHFR 677CC = a normal MTHFR gene
MTHFR 677CT = a heterozygous mutation which is one mutation
MTHFR 677TT = a homozygous mutation which is two mutations
MTHFR 1298AA = a normal MTHFR gene
MTHFR 1298AC = a heterozygous mutation which is one mutation
MTHFR 1298CC = a homozgyous mutation which is two mutations
MTHFR 677CT + MTHFR 1298AC = a compound heterozygous mutation which is one mutation from two different parts of the gene

8 years ago

I had four miscarriages and a placental abruption. It was then I had genetic testing and found to have MTHFR 677CT and 1298AC. At age 35 and 36, I finally had two healthy children on Folic Acid and Heparin. I was told after pregnancy I would be okay on aspirin. However, at age 38 I suffered a stroke and age 40 had a total thyroidectomy with a right neck dissection due to thyroid cancer. I am presently on Plavix and Synthroid. I have pushed through life with anxiety, depression, ADD but am hesitant to take any more medications. Any suggestions?

8 years ago

I had four miscarriages and a placental abruption. It was then I had genetic testing and found to have MTHFR 677CT and 1298AC. At age 35 and 36, I finally had two healthy children on Folic Acid and Heparin. I was told after pregnancy I would be okay on aspirin. However, at age 38 I suffered a stroke and age 40 had a total thyroidectomy with a right neck dissection due to thyroid cancer. I am presently on Plavix and Synthroid. I have pushed through life with anxiety, depression, ADD but am hesitant to take any more medications. I have asked several physicians, no one seems to be concerned. Any suggestions? I am sure what I should be taking.

8 years ago

Why do you (author) call it mutations? That is not correct! They are INHERITED variants.
Not very credible if you get these basics wrong…

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