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 - jcem.endojournals.org/conte...
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: