How important are genetic risks really?
This post is inspired, but not really related to this blog post: In what we trust. It is an interesting read, so go read it, but the one sentence that I want to focus on is this (emphasis mine):
The headlines seem inevitably to contrast starkly with the output of government and industry that seeks to quash our fears and to emphasise how doubling a tiny, tiny risk is no big deal.
With personal genomics getting big, I’ve been thinking about the impact of knowing your genes and the disease risk they carry. With the validated findings we have, the relative risks are all very small. Somewhere between 1.1 and 1.5, most of them. Having one variant over another might increase your risk of a certain kind of cancer from 0.1% to 0.15%. Is that really going to matter for you?
Considering that smoking has a massively larger relative risk, and that so many people still smoke, do you really think that they will change their lifestyle if we tell them that they are in a risk group due to their genes, if the increased risk is really that small? Do you think they people will change their diet if their increased risk of diabetes is that small?
I seriously doubt it.
What we learn from association mapping about the genetics of diseases is important for our understanding of those diseases, but — human nature being as it is — I don’t think it will matter much for the individual to know his personal genetic risk.
February 27th, 2008 at 4:13 pm
Thanks for picking up on my latest post. Interesting comment. The kind of shift in risk you and I allude to (e.g. of the order of 0.1% to 0.2% risk) is important to the scientists, but it’s nothing, like you say compared to the change in risk of lung cancer between not smoking and taking up smoking.
It irritates the heck out of me to see headlines proclaiming a doubling of risk with such and such an activity (contraceptive pill and hormone replacement therapy, being the cases in point) when that doubling is actually of a low risk activity in the first place. Buying two lottery tickets may double your chances of winning, but when your chances are 1 in 14 billion to start with, that’s not a great shortening of the odds.
db
February 27th, 2008 at 4:24 pm
Exactly, and I fear that misunderstanding this can do a lot of harm to serious research…
People who buy the hype about personalised medicin based on our new genetic findings will at some point figure out that we are not delivering what the thought they were promised, and that could reduce funding for our research. Not because the research is not important, but because it did not deliver what we never promised it would…
February 27th, 2008 at 4:46 pm
Just to be absolutely clear, I think I should add another comment here. I think that personal genome services like deCODEme and 23andMe are very cool and I think we at some point in the future will be able to use it for medical purposes, but we need to be realistic about what they can provide with our current level of technology and knowledge.
The variation we tag with the current SNP chips are all (relatively) high frequency variants, and for those, as a genral rule, we don’t expect major risks!
Knowing your markers can still give you some interesting information, though. You can track your genomic ancestry, for example. Again, be realistic here, it won’t tell you exactly where your ancestors came from or anything like that, but it will tell you a bit about the general area different parts of your chromosomes came from, and that is pretty neat in any case.
February 27th, 2008 at 11:03 pm
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February 28th, 2008 at 6:25 pm
[...] How important are genetic risks really? [...]
March 3rd, 2008 at 4:35 pm
I think that this post brings up a very interesting discussion point. The focus of the personalized medicine push has been on genetics. But what we are finding, is that genetics is only a small part of the picture, and is very complicated. For example: The differences in risk for developing lung cancer show a genetic risk factor — but, when you look at smoking data, smoking trumps genetics, and now there are no specific risk factors that predispose you to smoke-induced lung cancer (accounting for about 90% of lung cancers, btw). What this all means, is that the influence of the environment is quite strong, and can often trump genetic predispositions (at least on a population level). When are we going to start focusing on the importance of environment (and our biological reaction to it) as the key to personalized medicine? What I really want to know is… what diseases am I *NOW* in the early stages of, while I can still reverse the process? This can only be done by assessing the state of my system, and following it over time. Does anyone hear a “Systems Biology may be the key to Personalized Medicine” theme to this? That is where I think we need to focus.
Just my $0.02….
Owen
March 3rd, 2008 at 6:38 pm
I think this is a very good point, Owen. The environmental factors are often much more important for disease development than any genetic factor (at least as far as we currently understand). Really, we need to understand both the genetic causes as well as the environmental causes, and of course the interaction between the two. This, however, is probably much harder than it sounds.
I think we need to turn to systems biology to really understand any complex disease, but at this point we hardly know which components make up the system.
March 23rd, 2008 at 6:16 am
[...] my blog received a lot of traffic about this post from yesterday about the relative risk of disease genes. I wrote that the relative risk (RR) of the [...]