The New DIO2 Gene Test

Thyroid UK is very pleased to inform you that we are now working with Regenerus Laboratories Ltd in respect of the DIO2 Genetic test.

The DIO2 gene was researched in 2009 and the results were published in the paper entitled, "Common Variation in the DIO2 Gene Predicts Baseline Psychological Well-Being and Response to Combination Thyroxine Plus Triiodothyronine Therapy in Hypothyroid Patients" by V Panicker, P Saravanan, B Vaidya, J Evans, A Hattersley, T Frayling & C Dayan -

Firstly, you need to know that everyone inherits two copies of each gene, one from their mother and one from their father.

To explain this paper briefly, the DIO2 gene activates tri-iodothyronine (T3) and the researchers found that a tiny fault in this gene could mean that although the body gets enough T3, the brain doesn’t.

The researchers found that patients on levothyroxine (T4) alone felt worse if the faulty DIO2 gene was inherited through one parent and worse still if they inherited the faulty gene from both parents.

The patients on this study were given T4 only for a set period and then combination treatment of both T4 and T3. The patients who had normal genes did not feel any different on combination treatment. However, those who had one faulty gene felt better on the combination treatment and those with both faulty genes felt better still.

This means that there is a possibility that patients who are on levothyroxine alone and still have symptoms may improve with the addition of T3.

Because this faulty gene causes a deficiency of T3 within the cells, the usual thyroid hormone function tests will not show up a problem. This means that your TSH, FT4 and FT3 blood tests will look normal.

The study concluded, “Our results require replication but suggest that commonly inherited variation in the DIO2 gene is associated both with impaired baseline psychological well-being on T4 and enhanced response to combination T4/T3 therapy, but did not affect serum thyroid hormone levels.”

If you are still experiencing symptoms even though you are on levothyroxine, it might be an idea to discuss having this test with your GP although it is not available on the NHS so you would have to have the test done privately.

For more information on the DIO2 gene and the test go to:

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31 Replies

  • That is amazing that this can now be tested.This seems to be in my family.

  • Louise, is Thyroid UK 'our practitioner' for ordering this test? (like with Genova for example?)

    also, on the leaflet it states £60 for the test and £60 for consultation, is the consultation 'compulsory'?? as I'd like to avoid the extra £60 if I can :D

  • Me too! Not sure why you would need counselling - it's not the same as testing for a cancer related gene or other life threatening illness. If you have got the gene then you have a potential solution which is a positive outcome.

  • absolutely Janericat, counsel for what? for the potential 'distress' the result may cause you? what about all the distress we have anyway when our doctors refuse to treat us optimally :D

  • I agree.

    it's a bonus or stay-as-you-are 50/50 test.

  • One of the issues with a lot of gene testing is in the possibility of passing it on. That is something which could have quite an impact on some people.


  • yes Rod BUT: you can ask me the question 'will you have any children in future' and my answer will be NO I'VE BEEN STERILISED HAHAHAHAHA so I don't need counselling it's DONE ;) , and in regards to my son it could help him as he's hypo too :)

  • That's exactly my thinking too. If either of my children develop any of my symptoms and I have this faulty gene, I pretty much know how to help them. Surely that's a positive thing?

    But I do understand the point for those who haven't had their children yet. I went through this with something else (which I turned out not to have, it was my thyroid).

  • You are right that there are some situations in which the issues do not arise. But some people might be upset at the thought of having passed something on. Even if it is only a few, those who feel they have to factor this information into their lives do, in my view, need the possibility of counselling.

  • I hear what you're saying, but I still think it should be optional. :)

  • Just had the test carried out and the results were sent to my GP. I have this faulty gene inherited from my late Father. It cost sixty pounds. I am now having my children and niece tested. One of my son's and my niece were said to have ME. But now looking back my Father was never tested for thyroid disease and eventually died of liver disease. It was only when my husband said you have the same symptoms as he had. I had got used to feeling ill., as I put it down to menopause. It is only now that I know his Mother died at my age with these symptoms in the 50's. Pay the 60 pounds and your doctors will take notice. I fell into a Myxamadema coma at 51. Lastly they are really helpful when you phone to order the kit.

  • Very interesting that this test is now proving what some people might never have expected to find. I hope it helps set you back towards a road to recovery.

    I am interested in taking the test too for similar reasons.

    You mention the test being £60. Did you have the counselling too?

  • No counselling needed, the results are sent to your GP or Consultant. They will let you know when the results have been sent out . It takes a few days for the results to arrive at your doctors. Then if positive , see the GP or Consultant if you have one. Or ask to be referred to hospital to see a consultant. I now have a new GP as my old GP was made to retire. For me a blessing in disguise. Your GP will act on a positive result, I have lost my grandmother , great grandmother and my father with this gene. The women both died at 52.

  • A bit personal, but how do you feel now you know? I appreciate you may not want to answer. Can I also ask what action has been taken by your GP/consultant since getting the results? I have not had much help from either so far and I am autoimmune and that is inherited. My mother died prematurely.

  • Angry with old GP. New GP's have made both my son's make appointment's with a consultant. I am seeing my Consultant in November. But as I have just found out and am still recovering from the Spring, I intend to go private to see him on my return from holiday in 2 weeks to get T3 which my GP's are backing. My body and brain have good day's and bad day's if I try to do too much I will be flat on my back for 3 days. I have to pace my self. My energy levels have been shot away for years. This damaged gene answers so many questions. One sign is you would of always had trouble getting up in the morning with an alarm clock.

  • Thanks for insight. Its a difficult one altogether but I can only hope that it brings good to you and yours knowing the results and that off course the proper actions can be taken to improve things for you.

    Keep well and would be interested in knowing how you go as you are one step a head of me :-)

  • Will keep you informed.

  • Hi,

    I too have been told I have ME - I have been suffering for so many years...I am a newm member of this I am just learning.....!! And, there is a lot to learn, and, to be thankful for.

    For years I have had very limited energy levels so tired.. and my moods have been so eractic. I have had this 'gut feeling' about that i may have a thyroid problem for a long time...It is only now that I have found the information needed.. I am now going to arrange for the 'genes' test to be done... Why are our GPs so incompetent? I will let you all know of my progress - I have a good feeling (and gut!) about this....

  • Probably the best £60 you've ever spent! :)

  • Exactly, it answers all my problems. For me it was when I had a mini stroke and fell into a coma . Before that my Thyroid levels were coming back borderline. It only took 3 months to become so ill. 60 pounds is nothing compared to the being so ill at 51.

  • But, is this another test the GPs are going to take no notice of ???

  • No, not with our lot here getting on to the case ;)

  • Can ppl who are officially undiagnosed test for it, if the research report states than bloods will look normal with this gene?

  • Hi

    I have just searched for this test on this site and came up with this discussion thread - Hurrah - A few queries points though :-

    Is the test reliable and valid ? Can we tell?

    Am I right in thinking a single or double inheritance positive test would indicate the patient will do better on combination therapy OR does it show T3 only to be a better approach .It seems to be the former was part of the research not the latter?

    The discussion re the counselling is because the lab has to follow the "Common Framework for genetic testing"- I wonder whether we could use Thyroid UK as an "Advisor/Counsellor" or for those who see them Dr BDP or Dr S?

    Seeing my GP /endo would seem like a Big Deal but then I am in a cowardly mode at the moment.

    I am struggling at the moment on 30mcg early morning dose Lio only ( better than splitting it) and have been experimenting with adding in Nutri Thyroid with the idea NDT may be the next step. If the genetic test were positive( definitely lots of family history) then I thought I'd be better just to up the Lio - maybe this is wrong as a positive wouldn't rule out NDT.

    Mmm you've got me thinking


  • If you do OK on T3,Sarah you probably won't need to do it.

    Where it will be [really] invaluable is those stuck on 'T4 Stuck' GPs -who haven't heard of the 21st Century, quite yet!

  • Hi tegz - was doing better on T3 but have plateaued again :-( . Now my ferritin is up just in range and Vit D; B12 better I wonder whether I should be trialling NDT or just upping theT3.Infinitely better on T3 than on T4 but not there yet!

    I have adrenal problems post kidney removal in 1995 but NAX and NA support are really helpful and my morning cortisol is now in range - NT has been helpful in the past ( when probably ferritin was low ) but the adrenal issue seems to limit the effectiveness when I try an increase. Still experimenting - will post on new thread when I have results and ref ranges in hand next week.

    Wondered whether the genetic test would help me decide.

    thanks for your reply

  • I think Lynn says it below about the test- but you are up in front on this -so keep updating.

    The technical difference between NDT and Synth T4/T3 may simply be in the numbers T1 &T2 which no one seems to know too much about.

    T0 is Tyrosine and end of the line for use.

    Maybe the way the body responds is monitored by T1 or T2 output - and that's why NDT is better for some.

    Both Synth and NDT can still lose efficacy in time, so trialling is all you can do.

    The beauty of NDT, with all the doubts about how 'much of what' is running, is that you have a full house of T's to play with and perhaps some local 'inbuilt' feedback [T2/T1?] to assist matters.

    Nature knows best, don't we know ;)

  • Thanks again Tegz - so thinking further if someone inherits the Dio2 gene fault and the cause is a deiodinising problem then it might follow that you are less good at converting not only T4 to T3 but also T3 to T2 and so on to T1 and T0 - ah ha - in which case NDT could be really helpful. -

    However - if there is a genetic fault would this predict a lifelong battle, a gradual diminishing or key events catalysts to activate . .... more pondering :-)

  • Can't assume too much ,Sarah- the deiodinising may work the other way on feedback and become 'feedforward'...

    Reminds me of my old days on gun computers. ;)

    No wonder people [and the Docs] struggle to get right doses-it aint simples..

    Stay positive and just aim to find the right path through.

    Awareness is building all around :)

  • Hi Sarah, Yes, the test is reliable and valid. It's done by a reputable lab. It seems that if you have single positive test, you may do better with the addition of T3 but if you have double you will probably do better with the addition of T3. There has been no research on using T3 only for people with these genetic faults.

    Counsellors have to have experience of genetics so we couldn't be a counsellor and neither can Dr P or Dr S.

    It's all very early days and GP's probably have not heard of this problem. Some endos may not either. If we had the funds, we could send a letter to all endos about it!

    Can't really respond on your treatment - always best to get monitored by a GP.

  • Many thanks for this Lynn - much appreciated - will let you know what I decide :-)

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