Science Interviews


Thu, 10th Jul 2014

Susie Meisel - Obesity gene tests

Susie Meisel, UCL

Listen Now    Download as mp3 from the show Issues for genetic testing

Kat:: Now itís time to return to the subject of genetic testing. Dr Susie Meisel, also at UCLís Health Behaviour Research Centre, spent her PhD finding out whether providing people with genetic test information could help motivate them to lose weight. I started by asking her more generally about some of the challenges of understanding the glut of genetic information we now have.

 Susie::  I think at first, when the sequence was revealed, people thought it would be quite Ė I wouldnít call it simple, they probably thought itís going to be complicated - but from the experience that they have with genetics up to that point which is mainly Mendelian disorders where you get a certain probability to have the disease versus not.  I think people really expected that once we know the genetic code, that then we can really like understand why people get ill, and that it would be not necessarily there's one gene for this, but generally, they would have a pretty good idea why someone is being ill.  Then the reality of course was very different.  I think once the genetic code was revealed, actually, it turned out that itís much more complicated than just, you know, a few genes interacting and this is how you get cancer.  I think when we started out, we were quite naÔve about how complex human beings actually are and how complex disease can be.

Kat::  In the area that you did in your PhD, it was kind of understanding genetic testing and the implications of that for people understanding obesity.  Tell me more about that work.

Susie::  That was quite interesting because it was more like a Ďproof of principleí study.  We chose obesity because itís a condition that is familiar to a lot of people.  It is very strongly implicated by genes, but itís not this condition where itís one gene that causes you to become overweight.  In fact, it is a lot of genes.  At that time when I started my PhD, FTO was the gene that was the best researched one, which had a small effect but on a population level then would have a big impact.  I think this is why we chose it because itís a very emotional issue for people Ė why they are overweight, why they are at a certain weight, why they can't lose weight as easily as other people.

Kat::  So, tell me a bit about the study.  What was the gene variation you were looking at?

Susie::  So FTO, which was original called the fused-toe and obesity gene and now, itís fat mass and obesity gene.  Itís a gene which comes in two variants.  The higher risk variant on an individual level, it causes you to be about 1 kilo heavier.  So, if you're a homozygous, you have two variants of that allele then you are about 3 kilos heavier and have a 20 per cent higher lifetime risk to become overweight and obese than someone who hasnít got the higher risk alleles.

Kat::  How did you do the study?

Susie::  I did a randomised control trial as part of my PhD which had giving people this sort of genetic test feedback, the FTO result - so, itís only one gene - and generic weight control advice in the form of a leaflet that we designed specifically for this study.  And the intervention group got feedback and advice, and the control group only got the advice leaflet.

Kat::  What did you find?  What were peopleís attitudes?  Did having a gene variation that said they were more likely to be obese going, ďYep, thatís it.  I'm going to lose this weight.  I'm going to battle it.Ē?

Susie::  Yes.  It was quite interesting because people who did have the higher risk variants were indeed more motivated than those who had the lower risk variants.  However, there was no difference with those who had the lower risk variants to the control group.  And so, this really indicates that people can be more motivated if they get these higher risk results.  However, it doesnít reduce motivation and cause disengagement or genetic fatalism.  Sort of this, ďOh, I've got the higher risk gene variants and therefore, I can't do anything anywayĒ or ďI donít have the higher risk gene variants and therefore, I will be immune to becoming overweight.Ē  This is not how people think, and I think that became quite clear.

Kat::  Thatís quite interesting because thatís almost been a sort of slight perception in the media that, if you can blame your genes, why bother trying to be healthy?

Susie::  Yes.  Thatís sort of perpetuated.  However, when we did some research as well with overweight people specifically and their reactions to receiving gene feedback, most of them took part to kind of learn something about themselves and to understand their condition better.  They really found it was really a relief of guilt and shame and self-blame.  ďSo, itís not all me and my responsibility.  It is also my biology and I'm battling my biology.Ē  I think that sort of realisation made them then more motivated to really go on and do something about it.  I think thatís something that is for us as researchers reassuring that people donít have, at least for common complex diseases, it doesnít seem necessarily that itís all genes or itís all behaviour, but itís more complex.  They do understand that very well.

Kat:: As in your research and in other research thatís been done, even if people know something and are motivated, itís very hard to actually do something, put the cream cake down, go for a run.  Do you think that genetic information can actually make people change their behaviour or is it just a nice idea?

Susie::  I think from my research, I have to say, unfortunately, it seems to be just a nice idea at the moment.  We didnít find any impact on behaviour change.  However, I'm not sure because as you said, behaviour change is a very complex thing.  So, this was information for one gene, for a complex disease and I donít know, having that little bit more information of what difference it actually could make.

Kat::  Itís interesting that you mentioned that people can know things about their genome may be not motivated to change, but also, a good indicator of what's in our genes is our family history.  As well, you can see that say, your father had a heart attack, but you may or may not choose to do that.  Obviously, our genes aren't just our own gene.  They are our familyís genes too.

Susie::  Yes, thatís a very important issue I think that comes up now with whole genome sequencing, especially more and more with that.  Of course, weíve always known that having in close look at your family history would actually be more useful than taking a 23andMe SNP based test especially for diseases.  However, of course, for whole genome sequencing, itís then different because itís not just your genome.  Itís your family as well and itís a big question about how we communicate and who is communicating this because it might be that you want to choose testing but then your sister doesnít want to. 

So, what do we do then?  If anything is found, will we then not tell the sister because she didnít want to know? Or will we tell the sister and cause potential distress because sheís burdened with something.  But equally, if the person that had the testing is not telling, maybe she will feel guilty or he will feel guilty about not communicating that sort of information.  So, I think there are lots of issues that really need to be thought of and sorted out now where whole genome sequencing is really on the horizon, and it is definitely here to stay.  So, there's no question about that.

Kat::  And one of the incredible things is how fast things are moving and how slow things like legislation and policy are being to catch up.  What do you see are the really, really key urgent issues that need to be sorted as quickly as possible whether thatís research or policy?

Susie::  Itís really important to think about those ethical implications very well if you go down that routes of, like testing and it is about consent.  How are we consenting people?  I think it will really be, how do we communicate very complex information to people so they can then make an informed decision about what they would choose for themselves, but also perhaps for their families?

Kat::  And do you think we will move towards the kind of the Gattaca scenario where a child will have the genetic test done at birth and that will set the course of their life?

Susie::  Well, I'm cautious about that.  I would say at this point in time, probably not and hopefully, not.  But I think that genetics will play a much bigger role in medicine in years to come.  Of course, some people say the earlier you know, the earlier you can intervene.  But thatís again something for legislation and I think researchers and policy makers to very carefully think about what the implications of that would be also for a childís life, and a child doesnít have the right to consent yet.  They can't, so itís the parents and there are some issues about that as well that one has to think about before we move on to Gattaca.

Kat::  That was Susie Meisel from UCL.


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