Predicting the future

Domhnall MacAuley and Siobhan O'Neill discuss what genetic research could mean for you and your future patients

The local radio station telephoned. It was the Tuesday morning after a bank holiday and the waiting room was full. Muffled coughs and children's voices from the other side of the consulting room door warned that morning surgery would be busy. The computer screen flashed. Running late already. The programme researcher explained that they would like to do a story about our conference on primary care and the new genetics in May and could I do a live interview. It would last only a few minutes.

It was hard to think of a reason to decline. The university would benefit from exposure on the airwaves and the publicity could draw attention to our research programme. But, there is always a risk on live radio. The questions are unpredictable and interviewers are not always sympathetic to doctors. Besides, the purpose of our meeting was to draw attention to the uncertainty, and to explore the potential future impact, rather than trot out simple facts and sound bites. Anything I might say would sound vague and woolly--which is pretty much a reflection of where we are at the moment. The prospect of stumbling from one inadequate answer to another, punctuated by awkward silences and uncertainties, was hardly encouraging. We may know the basic science but the future impact of current genetic research is almost impossible to predict. To be adequately prepared I should really know all about the human genome project and the latest research findings. Instead, here I was, caught between the traditional world of general practice, the modern world of instant media access, and speculation on the future impact of genome research.

Difficult message to get across

So, what are the issues? The difficulties raised by genetic research reflect the downstream effect of almost any medical breakthrough. No medical discovery is ever as simple as is sometimes portrayed in the media and no advance is without some potential adverse effect. Most of all, the future impact is unpredictable. This is a difficult message to get across to a public whose expectation is of constant good news with medical science always working to everyone's advantage.

The tabloid headline which screams out that we have identified the gene for breast cancer brings hope to millions. This is a great scientific advance. But, there are other implications. General practice is about the personal perspective and how abstract scientific advances matter to the patient in the consulting room. It helps to think of it from your own viewpoint. If there is a strong history of breast cancer in your family and you have the BRCA1 or BRCA2 gene you are at very high risk of carcinoma of the breast. Confirming this genetic predisposition will change your life. Not only do you face the choice of regular annual mammography, but you may consider prophylactic Tamoxifen or having a mastectomy. It may change your view of relationships, having children, or even your commitment to a career. Similarly, if there is a family history of a particular type of carcinoma of the colon and you carry a mutation in the MLH1 gene you face regular colonoscopy for life.

Is this the future?

You have a choice

There are other genes which have a lesser effect on risk because of their reduced penetrance and where lifestyle may be more important. Imagine for a moment that you have a single gene polymorphism that gives you an increased risk of cardiovascular disease. You have a choice in your behaviour and lifestyle. Everyone reacts differently. Only you can decide if you would be more likely to watch your cholesterol, go jogging, and monitor your blood pressure. As a fatalist you may decide to enjoy a life of sloth, a diet of cream buns, and overindulgence. Health promotion could take on a whole new meaning.

Pharmacogenetics is another buzz word. The drug industry has invested huge resources with a view to focusing therapeutic interventions on those who will respond and in trying to identify those who may have an adverse reaction to a drug. Another area of huge potential but where, at present, the future is speculation.

There are some aspects of genetics testing we can predict. Every genetic test has implications beyond the individual, extending throughout a family. For every positive genetic test there are relatives who must deal with their own anxiety, concern, worry, and health fears in their own way. These are issues for general practice, far removed from the glamorous world of genetic research. For some there will be cancer phobia, frequent attendance, and multiple investigations, but for others it may be reflected in consultations about family, risks to their children, difficulty in buying a house. The hidden morbidity of any scientific advance.

We cannot undiscover the human genome

Would you like to know the future? Perhaps. But, think about it. Life has many unpredictable twists and turns and, when something unexpected happens, we sometimes wish that we could have known it was going to happen. On reflection, you may decide that we are better off not being able to predict the future, that you would rather not know the problems that lie ahead. There are huge differences between single gene conditions such as Huntington's disease and other polymorphisms which identify a slight increase in risk. But the human genome project has changed medical risk projection and these genetic advances present some of us with the awesome potential to predict a likely cause of our own death. Perhaps we would rather not know. But, we cannot undiscover the human genome, and are just beginning to understand the implications of what we have uncovered.

Domhnall MacAuley, professor of primary health care

Siobhan O'Neill, research assistant, Institute of Postgraduate Medical and Health Science, University of Ulster


studentBMJ 2001;09:261-304 August ISSN 0966-6494