The genetic 'trickle effect'

'Biology's Apollo landing', 'the outstanding achievement of human history' and the 'language in which God created life': just a few of the comments that accompanied the unveiling of the rough draft of the human genome in June 2000. By April 2003, when the final version was published, the media attention had diminished slightly, but scientists and governments alike continued to promise that genetic knowledge would transform medicine. Some of the predicted benefits included medicines and healthcare advice tailored to a person's genetic make-up, and new treatments for common illnesses such as cancer and heart disease. But now the dust has settled, the message from scientists and policy makers appears to be changing, at least from those who spoke at a meeting on genetics and medicine held in London last week.

Far from overhyping the effect of genetic information on healthcare, experts speaking at the Royal Institution's public event 'Our genetic future' stressed over and over again that it would take decades before the results of the human genome have any real effect on our lives. It is true that much remains to be discovered - common diseases, unlike rare, single gene conditions, are the result of complex interactions between genetic and non-genetic factors. And scientists still only understand the function of a minority of our estimated 25,000 genes. So it is essential that a balance is struck between making unrealistic promises and predicting how genetic data might impact on medical treatments. But it is perhaps misleading to suggest that new knowledge of our genetic make-up will contribute nothing to medicine for another 20-50 years, when there will be a sudden avalanche of advances.

As in all areas of science and technology, the knowledge that will form the basis of the 'genetic age' will arrive as a trickle, not a deluge. For example, we already know the genetic changes that affect a person's response to the painkiller codeine, and some of the genetic variations which can affect the risk of Alzheimer's disease, depression and heart disease. The challenge for policy makers and regulators will be to decide whether to wait until this information has a clear, cost-effective use in routine healthcare, or whether consumers should be able to access intermediate genetic technology in the interim. Twenty years ago, people who bought the first personal computers did so because they wanted to use the best available technology, even though it was predictable that machines with vastly increased processing power and storage were on the horizon.

Several companies are already offering 'genetic predisposition' tests over the Internet, a trend that is almost impossible to regulate, and one which looks set to continue. As one woman in the audience commented at last week's meeting: 'If I knew I had an increased risk of getting Alzheimer's disease, then I might start writing my book right now'. Personal genetic information, if protected from misuse and accompanied by an explanation of its limitations, could be useful to individuals well before it is offered routinely to everyone.