The Trialnet study, which many of us with T1 children are familiar with, has been generating some interesting data on genetics. Their most recent statistical analysis had some interesting conclusions:
- Type 1 and LADA appear to be different diseases, since they are associated with different distributions of alleles:
"This is clear evidence that type 1 diabetes after 30 years is not just a delayed version of type 1 diabetes before 30. "
- The authors were able to come up with a genetic metric, the GRS, that was strongly predictive of the development of diabetes:
“Participants with GRS cutoffs of less than 0.25 had a 74% likelihood of not developing T1D within 5 years, vs a 56% chance among those with GRS scores of 0.25 or above (hazard ratio, 0.57; P = .0012).”
There is another metric, the DPTRS (which is not purely genetic but also looks at other factors). Those with a DPTRS score of 7 or more are highly likely to develop diabetes:
“those with scores above 7 are already highly likely to develop type 1 diabetes (70% at 5 years, 93% at 10 years).”
We have recently argued about genetics and environment in T1D. The fact that these metrics are so predictive makes me believe that there is little environmental and much that is genetic in Type 1 Diabetes.
The new study can be found here:
Very interesting study, thanks for posting. Most physicians I speak to believe that genetics are an 80%+ factor in things like diabetes, heart disease, cancer, etc. In diabetes I would think the environment can provide the trigger in a number of cases, but the genetics dictate what you are at risk for.
With these kinds of numbers, I would think that the trigger possibly merely determines if you get diabetes in 2017 or 2019. The odds seem pretty overwhelming, at least for these combinations of factors.
I think it’s more nuanced than that—it means that that is true for some people/genetic profiles (i.e., the people with a genetic risk score over 7). If you have a high score on those genetic markers, yes you are very likely to develop diabetes and probably environmental triggers are more a matter of when than if. But people with lower scores might develop it, in which case they have much lower percent chances of doing so, and environmental factors/triggers may have played a much more important role. I suspect the former cases are likely the folks with T1 running through their families, whereas the latter cases are the people like me, with T1 and absolutely no family history of it and minimal family hx of autoimmune disease.
This is interesting to me in light of the childhood-onset versus adult-onset and A1c attainment among adults discussion that took place here recently.
I do not have any relatives, even going back three generations, with T1D, but I do have relatives with other autoimmune diseases. The presence of any autoimmune disease makes additional autoimmune diseases more likely. Genes from those relatives may have been the cause of my T1.