Genetic Factors can Predict Risk of Heart Disease
On biomarkers and genes: the recent discovery that there are genetic factors that can predict a person’s risk of heart disease.
Recent articles in the prestigious academic journal SCIENCE from two separate research groups have been picked up and disseminated to the public by the New York Times. These studies suggested that certain genetic markers were found that could reliably determine if people of European descent were at risk of developing heart disease. The suggestion is that a chromosomal marker or genetic variation was associated with a 20% risk of heart disease, and if two such markers were present the risk increased to 60%. What do these new findings mean to the general public?
The answer at this point is very little. There is a great deal of excitement about the Human Genome Project and all of the information that it will eventually give us. I think that the key words are “Two rival teams of scientists have discovered…” and this usually means, unfortunately, that patients are at stake rather than a great scientific breakthrough.
The goal of the Human Genome Project is to determine the “normal” chromosomal make up of the human being. With such information, we will eventually be able to determine the origin of some diseases. If a certain gene tells our body to make an abnormal protein that clogs the kidneys and weakens the heart, then we can develop methods that “knock out” the offending gene. This would be a lot better than our current treatments that manage the results, but not the cause. Another goal would be to detect abnormalities that make us more susceptible to certain diseases. Wouldn’t it be nice to save all colonoscopies and mammograms by having a simple blood test that identifies those at risk of having problems? This long-term project, however, will take many decades to enable us to change our diagnostic regimens and establish new types of treatment targeted to the individual patient.
It is quite premature to accept these “discoveries,” as many such observations have led us down paths that have turned out to be dead ends. We have many more markers for the development of disease than we did years ago and very few have been useful additions to what we had before, though some of them have given us ideas about the mechanisms of diseases. The utility of most of the recently tested biomarkers has at best been modest. Your physician is using some “biomarkers” now that will be supplanted by newer and better ones over the years, and gradually the Human Genome Project will improve a physician’s ability to diagnose and treat disease. Unfortunately, scientific progress is slow and steady and the newspapers' overestimates of the importance of our “discoveries” and “observations” are used by industry to obtain venture capital. We physicians become very excited by the possibilities of new options to treat diseases better, and all of us are awaiting the next great developments expectantly. Unfortunately, the prospects of getting a Star Trek ‘tricorder’ or the rapid and seemingly endless test results that the producers of CSI come up with each week are not realistic.
In summary, genes do have a role in the development of disease and malformation. Eventually we will be able to target the bad ones with drugs, but we have a long way to go.