Genetic Future

Genetic genealogist Blaine Bettinger has a fantastic post dissecting and contextualising a rather worrying result from his personal genomic analysis: a 50-60% increased lifetime risk of type 2 diabetes.

Blaine is unfortunate enough to be among the 1-2% of individuals who carry two risky versions at each of three major risk variants for the disease. (It’s worth noting that type 2 diabetes risk is determined by many different genetic variants, most of which remain unknown, as well as environmental factors – so Blaine’s discovery is very far from a certain diagnosis of the disease.)

Blaine’s attitude towards the results is admirably pragmatic:

I, personally, am not afraid of my genetic information. I’m not afraid of any potential psychological effects it might have, nor am I afraid of any repercussions of sharing my genetic information with others. It is certainly clear that I lost the genetic lottery when it comes to diabetes risk, but there is no genome so perfect that it lacks at least one serious risk.

[...]

For me personally, interpreting my genotype is no more dangerous than the receiving the results of a home glucose test. Indeed, the results of the glucose test represent a current reality while the genotype merely suggests a future possibility.

I also applaud his decision to share this information with the world, a very personal way of demonstrating the spirit of openness to genetic data that he has consistently advocated in his posts. I completely agree with his reasoning here:

Although I won’t go so far as to say that there is never any danger to anyone upon receiving genetic information, I will go so far as to say that it should be the individual, not the government, that decides whether the danger exists.

Amen.

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Comments

#1 Keith Grimaldi
January 8, 2010

Thanks. It’s interesting because here we have both genetics and family history. What would the naysayers say (apart from nay) about the results? Ha! – don’t need the genetics, we have family history already. Really? What does Blaine learn from his results? He has, maybe, a raised risk of diabetes type 2, 36 people out of 100 with his genotype for these genes will get (do they mean did get?) diabetes, so 64 people won’t (or didn’t). The genetics don’t really tell us that whether Blaine himself has an increased risk or not – but then neither would family history. Of the 64 genetically similar people who won’t/didn’t get diabetes there will be environmental reasons – this nice paper looks at diet plus diabetes GWAS SNPs and nicely shows the environmental influence (http://www.ajcn.org/cgi/content/abstract/89/5/1453).

Blaine now has genetics plus family history, the genetics may be warning him that he really needs to pay attention to the latter, or vice versa but it looks like the genetic component of the family history has not skipped him. With the Liu paper though, and many others from similar studies which I hope will be coming along soon, he can determine his fate by making sure that the environmental components do skip him. Well wouldn’t he have done that anyway? I don’t know, only he can say, but since family history exists and persists it would suggest that many with a history don’t prevent it – add the genetics and I would suggest that we have an excellent tool for prevention.

But family history is better isn’t it – it is the product of both genes and environment? Not always. A Pima Indian moves from Mexico to his cousins in Arizona, two generations later a family history of a disease that he/she had never heard of is now established in his/her lineage.

OK the genetic results look interesting but how do we know they will be really useful – will they actually have the magic of…clinical utility? Let’s find out by finding a few thousand people with a similar high risk profile, in some we’ll use the results to guide prevention, in others we won’t, plus all the other controls required etc etc, and we’ll wait, and wait, and wait a bit more (Blaine is not so old I don’t think), then we’ll find out 10-20 years later, but at least we’ll know and after all “if RCT data are considered necessary to understand beneﬁts vs. harms for a particular application, then so be it” (http://bit.ly/6jwZyE)

Has family history as a preventative tool for diabetes ever been subjected to an RCT of the type being demanded for genetic profiles, for each particular application? Has it been tested for potential harms (worried well, false reassurance and all that)? These are real question, I’d like to see the designs to understand if they could be used in genetics.

Personal genomics will make it through the difficult early years – maybe it was Henry Ford, or maybe not, but to paraphrase…if he had listened to the transport industry at the beginning of the last century he would have been asked to develop faster horses
#2 Daniel MacArthur
January 8, 2010

Hi Keith,

Fair points all. Regarding cases where genetics trumps family history, perhaps the best example is recessive diseases such as cystic fibrosis: most people with CF have no family history of the disease, because very few of their relatives are unlucky enough to have inherited two mutated copies of the CFTR gene.

It’s clear that there is a need for studies exploring the effects of genetic risk information on health outcomes, but it is ridiculous to argue (as Khoury did in his recent debate with Kari Stefansson) that we need to wait for the results of these trials before people can be given access to their own genetic data.
#3 Blaine Bettinger
January 8, 2010

Keith – very interesting and thoughtful comment!

I can’t say how others will or do respond to their genetic information, but I can tell you how it was for me. I consider myself to be a moderately intelligent person, but up until this point in my life (I’m 33) I’ve largely ignored the environmental factors for type 2 diabetes. This despite the fact that it has killed a member of my family! But, for whatever reason, realizing that I have these serious genetic risk factors spurred me into action. I’ve made some serious positive life changes as a result of my genetic information, even though I knew beforehand that those changes needed to be made.

Although family history most certainly has its place, it’s not the only answer for everyone. It appears that at least some people will respond to genetics more than they will respond to family history.

What if I hadn’t been allowed access to my genetic information, or had decided not to jump through whatever hoops the government set up for me? I’d like to say that I still would have made these positive life changes, but I’m not so sure.

Although Dr. Murphy just posted today that “Your genome is essentially worthless right now,” (
http://tinyurl.com/ycnkcbn) I couldn’t disagree more. Although it sounds a bit dramatic, my genome has potentially saved my life.
#4 AMac
January 8, 2010

Great post by Blaine and excellent comment by Keith, above. From a public-health perspective, one of the biggest questions is what Keith highlights, What will people like Blaine do in terms of lifestyle changes (that they wouldn’t have done without genome-based knowledge of risk)? How will such actions affect long-term health?

Makes me want to see what Bob Green’s group at B.U. has published recently; he has been running a study to look at the effects of knowledge of ApoE genotype on people’s lives (APoE being a strong predictor of risk of Alzheimers disease). Though “what to do” in terms of modifiable environmental factors is much less clear in terms of AD than is the case for Type 2 diabetes.
#5 Keith Grimaldi
January 8, 2010

Thanks AMac. Daniel I completely agree with you that it’s ridiculous to wait. We all need studies, industry needs them for commercial reasons and the consumers for confidence. Studies will make the products better, it doesn’t mean that they have no value now. It would be more helpful expending energy on practical alternatives instead of continuing to argue for impractical RCTs.

In their article referred to they say “absence of evidence is not evidence of absence” – clever(?) soundbite but not an argument and not relevant – but, i don’t believe it is true anyway, not in this case. Since 2001 some there have been very strong opponents of personal genetics/DTC who have been searching but not finding evidence of harm. As far as harm is concerned, consumer protection works both ways – delaying a potentially useful service because “it might” do harm is potentially harmful itself.

Seat belts can and do cause harm, some people would have been better off without them. Enough with genetic exceptionalism (even though it is exceptional in many ways!) – a vain wish, but at least there is good leadership from the likes of the UK HGC and the Code of Practice Proposal: http://bit.ly/8I8xlN. If they were widely adopted then a lot of the murkier offerings would go away.
#6 Keith Grimaldi
January 9, 2010

Thanks Blaine for the follow up, it’s very interesting to know how you will respond, and a satisfying result especially because the lifestyle changes made now will certainly be less dramatic than those that would be required by leaving it too late. There is stuff and nonsense about creating the “worried well”, but perhaps a lot of the well have a good reason to be a bit worried and perhaps the genetics will help them to learn more about what to worry about and how to do it – and become less worried in the process!

AMac – thanks for pointing to the work on AD/APOE, you’re right, it will be very interesting to see what are the responses to testing for this quite controversial gene. As you say there is no well defined intervention, there are some interesting pointers but nothing solid, this doesn’t necessarily make the APOE gene knowledge useless to those who want to know it
#7 Keith Grimaldi
January 11, 2010

Larry Parnell has an interesting comment on this and their gene-environment work on TCF7L2 over at his blog http://bit.ly/90Jh3i
#8 shashank
February 5, 2010

Here is a link to more information about the genetics of Long Chain 3 Hydroxyacyl Coenzyme A Dehydrogenase Deficiency that was prepared by our genetic counselor and which has links to some useful resource for those dealing with this condition: http://www.accessdna.com/condition/Long_Chain_3_Hydroxyacyl_Coenzyme_A_Dehydrogenase_Deficiency/229. There is also a number listed for anyone who wants to speak to a genetic counselor by phone. I hope it helps. Thanks, AccessDNA