We have had a number of posts recently about the various DIO genetic variants that might affect our thyroid health.
I've created a blog entry which consists - largely - of a series of links to further information about each of the Single Nucleotide Polymorphisms (SNPs) you are most likely to see.
Not because I understand - I really don't - but to provide a starting point. So you can see which SNPs are known, and how find out more information.
helvella - DIO1, DIO2 & DIO3 Variants
How to find out more about the DIO1, DIO2 and DIO3 genetic variants.
Thanks for that helvella , it's a really complicated subject and not at all easy to understand. Some of those SNPs are better known to affect thyroid hormone production than others and generally those are the ones tested in thyroid gene tests, along with other SNPs of other genes that are known to affect thyroid function eg rs1360780 (gene FKBP5) that regulates cortisol and rs4704397 (gene PDE8B) that's involved in TSH signalling. It gets particularly complicated because we have two copies (alleles) of each gene. If you have the same copy of each allele, you are more likely to see that expressed in a person's body than if you have 2 different alleles where either could be expressed or a combination of both. But we also have to remember that none of the genes/SNPs work in isolation and other genes can turn up the action, turn it down, or switch it off completely. So at best, these tests can tell you if have a higher, average or lower risk of them affecting your thyroid hormone production. I hope I made that clear enough and haven't added to the confusion.
In time, we'll probably look back at this and be amazed anyone took seriously such a naive view as we currently have!
If ever I decided to look further, I'd want my whole genome sequenced. When I first got my 23andme, it was interesting but the number of times I found a reason to want to know something that was not part of the analysis drive me mad. So either a single and highly specific test. Or everything.
I agree. Don't doubt that for a minute. I took my 23andMe raw data and put it into Self Decode, which has given me a whole load more info, but like yours, it's not 100% complete. Maybe some day soon someone will do that a lot cheaper than it is currently. Until then...
I’ve been quoted £1,500 for “everything”. That was actually 3 years ago.
It’s been suggested that I carry the CDH1 gene which is linked to Invasive Lobular Breast Cancer, Diffuse Gastric Cancer and, more recently Thyroid Cancer - although research into the latter is not conclusive. I was diagnosed with IL BC and Thyroid Cancer in 2011/2012 (as two distinct primaries). My father and grandfather both had Gastric Diffuse Stomach Cancer and subsequently died of carcinomatosis at 70 years old.
Genetic testing to ascertain whether I do carry CDH1 would be a significant step forward in obtaining a diagnosis for as yet unexplained gastro symptoms with which I’ve been hospitalised four times since Christmas. Extensive investigations continue but sadly HDSC like IL BC only reveals itself in late stages. For example IL BC doesn’t present as lumps and if it isn’t picked up by routine mammogram is only found when lymphatic involvement occurs. Similarly, HDSC develops in several parts of the stomach and spreads rapidly and it is usually only then that diagnosis is made. I know that we shouldn’t use personification when describing the insidious behaviour of malignancies, but some cancers are sly, creepy little ******* and will do anything to avoid detection. Such is the nature of mutation for survival.
So why am I not arranging for CDH1 testing now? Because quite simply I don’t want to know. If I do carry the gene, the advice would be immediate gastrectomy. If I don’t, I’ll take my chance. If I had children, I’d feel differently.
I see the time rapidly approaching when genetics is a routine part of diagnosis and prevention. The implications of this are huge and take us into an Orwellian world which is an alarming prospect
You can get a whole genome sequence for £500 now. (Though that is, I think the 30-times rather than the higher-times specs. required for definitive analysis.)
Whether or not to get our DNA analysed is a difficult issue.
There are the issues we know and suspect regarding these DIO genes. The problems there being persuading a doctor to accept the DNA analysis and its implications, plus the possibility that NOT have one of the known DIO variants doesn't mean you don't have another variant somewhere.
But at least there is some sort of plan of action you can work towards.
Far more difficult if you are in the "no idea what to do" category - and you have something that seems to be categorically bad.
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DIO2 and DIO1 results from ancestry
DIO2 gene
