Jeremy Laurance: Genetic risk profiling may be harmful if nothing can be done

For a man about to learn whether he was under a death sentence, Stephen Quake was remarkably cool. Asked how he felt about receiving a detailed breakdown of his chances of developing any one of 55 diseases he replied: "It's certainly been interesting."

How typical of a scientist. But those of us who are not scientists may have a different response. Analysis of your genome could reveal you were carrying a gene for Huntingdon's disease, a condition that kills people in their 20s and for which there is no treatment. Would there be benefit in that?

This is the fundamental difficulty with genetic risk profiling – the information may be valuable in some cases, allowing patients to protect themselves against increased risks (as Stephen Quake has done by starting treatment with statins to prevent heart disease). It may enable doctors to re-emphasise messages on diet, exercise and smoking for patients with a predisposition to obesity, diabetes, or lung cancer – environmental causes that have a far bigger impact than mere genes.

But in others, it may be harmful when there is nothing that can be done. In this case the only outcome is that the individual lives are under the shadow of the threatened disease.

How is the information to be shared? If I have an increased risk of diabetes, it will be of importance not only to me but also to those who share my genes – my children and other relatives. Should they be told?

There are other difficulties. Doctors find it hard enough explaining the risks of drugs or operations to patients in terms that are comprehensible. How will they cope with the huge quantities of data involved in a whole genome analysis?

In an opinion piece published with the paper in The Lancet, Professor Henry Greely of Stanford Law School estimates the average person might need information on 100 genetic risks uncovered in analysis of their genome. Even if only three minutes per disorder is allowed, the consultation would take more than five hours, not including the background research. How can this be provided and who will pay for it?

Whole genome sequencing is already occurring and will soon be used in medical practice. The genie cannot be put back in the bottle. But dealing with the new technology will present many challenges. It is time to start thinking how to deal with them now.