Personalising Medicine through your Genome

The Lancet has published a study into the benefits of looking at your genome to help personalise your medicine. Dr. Euan Ashley from Stanford University School of Medicine joined...
02 May 2010

Interview with 

Dr Euan Ashley, Stanford University


Ben - Also in the news this week, the Lancet has published a full clinical assessment of the benefits of looking at your genome to help personalise your medicine.  Dr. Euan Ashley from Stanford University School of Medicine joins us now.  Hi, Euan.  Thanks for joining us.  Haven't we been finding genes related to disease for years?  What's actually new here?

Euan - Well, thanks very much for having me on the show.  I think this is the first time that anyone has really had a whole genome available for an individual.  The task we set ourselves was - what if a patient comes in to a doctor's office with his or her whole genome, what will the physician be able to do?  So we tried to integrate all the associations with genes and disease that have ever been described in a way that we could apply to this one person's genome.  Human genome

Ben - And is it just the diseases that we can look at or can also tell a bit about how they might respond to certain drugs?  

Euan - Yeah.  This is the topic of so-called pharmacogenomics, using the genome to help try to choose a better drug and personalise medicine for the individual.  But it can do other things other than just choose the best drug.  It can do that on the basis of the best effect for the drug but also hopefully, help to avoid side effects.  In the particular patient in our paper, he fell just short on the regular criteria for recommendation of cholesterol lowering medication.  But when we looked into this genome, we found increased genetic risk for coronary artery disease, so we moved ourselves towards recommending that.  We looked in the genome to see whether he would respond well to one of those cholesterol lowering meds and then we found variance in his genome that would suggest he would.  And more than that, we actually found variance that suggested a low risk of side effects and I think this is really what 'personalised medicine' of the future will begin to look like.  

Ben - We've had a sequence of the human genome for a little while now.  Why only now are we starting to look at it from this personalised medicine perspective?  

Euan - Well, I think that the informatics challenge has been very significant and of course, all the time, this information is changing and we're gathering together information about new variants.  This was only the 5th human genome that has ever been sequenced and really, it's only a few years ago that it cost millions of dollars.  In fact, in 2001, when the first draft Human Genome Sequence came out, that project was $3 billion, although maybe 3 or 400 million were the sequencing cost.  But this particular genome we looked at cost only $50,000 to sequence and even since we did that last year, the cost has fallen in half and we believe it will continue to fall so that in the next few years, it's really literally a few hundred dollars.  

Ben - So that sounds very promising.  I'm glad to see it's getting a lot cheaper but how do you prepare somebody for this?  You're telling them an awful lot of stuff that they won't have known about themselves, about their risk for diseases.  Does somebody need counselling in order to actually take all this in?  

Euan - Absolutely and this is something that we took very seriously.  We did provide counselling to this particular patient.  I think it's a challenge really in a quantitative way.  We've always given genetic counselling to patients when we do genetic testing but this is really on a whole different scale.  They could potentially find out about hundreds or thousands of disease risks and we need to make sure that patients and physicians are going ahead in a way that their eyes are open and that they understand what they might find out.  This is - at the end of the day, not a cholesterol test where you might find out four or five things.  You're dealing with 6 billion data points and really maybe, 2 ½ million variations from a reference genome.  And so, there's going to be a lot of information and it's going to be a lot to take in, and I think we have to take that part of it very seriously.  

Ben - So what are the challenges for you now?  What's the next step?  

Euan - Well, in the original paper with this genome, there were there three authors and they sequenced the genome for $50,000 in five days, and the paper that just came out in the Lancet this week, there were 30 authors and it took us months and months, many hours of manual labour to comb through this genome.  And I think what we would like to be able to do is automate that and many of the algorithms that we have written are easily and readily automated, and we started to work on that for the next genomes that are coming forward.  

Ben - So the sequencing is getting very quick but it's this analysis that we've really got to speed up.  Thank you ever so much for joining us, Euan. That was Dr Euan Ashley from Stanford University on what could be the future of personalised medicine.


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