Twin with ME/CFS wants to be a research subject

[Utsikt]

I was wandering about the obvious things such a different sex twins (or more), something most people will have come across in their lives, which per definition cannot be identical.

There are very rare exceptions:

Monozygotic twins of opposite sex - PubMed

Although discordant karyotypes are known in identical twins, cases involving differences in sex phenotype are rare. We studied identical twins with the 46,XY karyotype - a male with mixed gonadal dysgenesis and a female with "pure" gonadal dysgenesis. The testis-determining SRY gene was present...

pubmed.ncbi.nlm.nih.gov

 

[Sasha]

I have always used 'twins' for both types, identical and non-identical or monoygotic and dizygotic.
He is potentially of interest whichever in that studies often make use of differences in concordance between the two types. If only a small number of pairs are available then dizygotics would probably be more interesting to see which uncommon genes might show up in only affected individuals.

Wouldn't you need a whole ton of them, though?

 

[Jonathan Edwards]

Wouldn't you need a whole ton of them, though?

You tend to need quite a lot for any genetic statistical study. However, one person in forty is a twin. Of the 16000 people in DecodeME 400 should be twins. The big problem with genetic screening studies like GWAS is that you have to make such big corrections to your p values to avoid false positives. Once you know what genes you are interested in - maybe ten instead of ten thousand - then numbers needed are a lot smaller, ay least as I understand it.

 

[Cinders66]

There was a UK child case of twins girls in the news a few years ago. I think that one Of them had got m.e age 8 and the other is fine. It has relevance here but i am also keen to collect it for a letter but can’t find this newspaper article. If anyone has it can you please post it.

 

[Trish]

One potential problem with twin studies for ME/CFS is that the healthy twin may be just as genetically predisposed to ME/CFS as the other one, just hasn't yet had the right trigger, and may never do. I guess that's the case for all genetic ME/CFS studies. All we can say is that the healthy ones don't have ME/CFS yet, not that they will never get it.

 

[Jonathan Edwards]

One potential problem with twin studies for ME/CFS is that the healthy twin may be just as genetically predisposed to ME/CFS as the other one, just hasn't yet had the right trigger, and may never do.

Indeed, although I suspect that is relatively unlikely, especially if they live in the same house. What is much more likely to be important is that their immune system just doesn't happen to have randomly generated lymphocyte clones that trip a persistent feedback error. The immune system runs on the basis of producing things at random and seeing what works. Most of the time the control systems pick out the useful clones. But the system is so complex that there are bound to be built in bugs.

Popular medical science always talks of genes and environment, but random internal factors are at least as important - as any good epidemiology textbook will point out.