Thanks to SimulConsult founder Michael Segal MD PhD for this guest post.
A British expert on genetics makes some claims that are likely to come back to haunt him, but also makes an important point that I think is correct. See Genetic research in a “blind alley” in search for cures for common diseases.
Professor Steve Jones, one of Britain’s top geneticists, said the belief that a few genes held the key to ridding the world of conditions such as cancer and diabetes has proved to be “plain wrong”.
In most cases hundreds of genes are responsible, and often they have less effect than other factors such as diet, lifetstyle and the environment people live in.
“Just a couple of years ago, there was real optimism that a new era of understanding was around the corner,” he said.
“That did not last long, for hubris has been replaced with concern: like Macavity the Mystery Cat, the evidence of genetic inheritance is clear, but the genes themselves are just not there.
“Of course there have been some successes, but it is the ‘cure all’ aspect of the work that has proved unfounded.
Scientists embarked on a search for rogue genes responsible for just about every modern malady, hoping such conditions could be blamed on a small set of genes – which could then lead to a cure.
But the more they investigated, the more complicated they realize finding a cure would be.
Jones’ article is here.
After the famous sequencing of the double helix, the hunt started for the genes behind the illnesses that affect most of us – stroke, diabetes, cancer – as well as multiple sclerosis and a variety of brain disorders.
The hope was (and five years ago, it was a reasonable one) that such conditions could be blamed on a small set of common genetic variants. Track them down and we would begin to understand what had gone wrong, diagnose patients before symptoms appeared, and perhaps even come up with a few cures.
That part of the analysis is likely to come back to haunt him, but this part is a good criticism:
The logic was to search the double helix for about half a million variants that could be used to set up a grid of diversity, scattered across the whole genome. This could then be scanned using a magic “chip”, which could identify thousands of changes at once to see whether one, or a few, of the molecular milestones might predispose a given individual to a particular disease. If so, the actual gene responsible could be close to the telltale marker.
The latest version of this grid, produced by what is known as the Wellcome Case Control Consortium, involves 120,000 samples, taken both from invalids and those who are perfectly healthy. It is a huge – and expensive – operation. Just a couple of years ago there was real optimism that a new era of understanding was around the corner. That did not last long, for hubris has been replaced with concern: like Macavity the Mystery Cat, the evidence of genetic inheritance is clear, but the genes themselves are just not there.
Such gene chips are actually quite a crude measure of what I expect we will find – single base substitutions that produce some common diseases. I think the gene chip criticism is valid but the “no simple answers” part will be right in some areas and wrong in many.April 28, 2009