The Latest edition of Mendel's Garden is up at Scienceroll. If you haven't seen it, the Gregorian Rap All-Stars video is a must see!
Sunday, August 5, 2007
It's official. I can say without any doubt that the gene TCF7L2 is somehow implicated in diabetes. Another whole genome association study was performed and results were published in the American Journal of Human Genetics.
The study which performed because there only exist a handful of genes that have been implicated in the genetics of diabetes. These include PPAR gamma, TCF7L2, KCNJ11, CPN10, FTO. And because GWAS is hot now. They selected 4 populations, all Caucasian. 200 Finns with diabetes and 200 without, similar numbers of Ashkenazi Jews, 100 soccer hooligans from Manchester and 99 affected Brits, as well as 100 Germans with diabetes and another 100 without.
What they found was not surprising. TCF7L2 SNPs rs7903146, rs7901695 and rs122255372 were all replicated as linked again with ORs of 1.6-1.7. They also found several candidate loci. None which were that impressive when attempted to be replicated.
So, what does this all mean? Well it means that there is an increased risk for diabetes if you have any of the aforementioned changes in your TCF7L2 gene. But how does that help us? Now that it is shown to be linked, we need some data on how to prevent diabetes in the carriers of altered TCF7L2.
Does anyone have good data on this?
The Sherpa Says: Sometimes I do eat humble pie. That being said, I will not recommend TCF7L2 testing for anyone. Importantly because there are several SNPs associated, not just the SNP that deCode tests for. There is more to this diabetes story than meets the eye.