alternate allele with adequate levels of enzyme. This information can be used to discover exogenous agents that increase risk for a particular disease. The allele that determines the lesser-detoxifying enzyme would occur in higher frequency in those diseases for which the exogenous agent in question increases risk. This technique could focus attention on the elimination of these dangerous elements from the environment. I will provide an example of this phenomenon later in this chapter.
The rapid progress of the Human Genome Project opens the possibility of the identification of potential disease in clinically normal individuals, and its prevention before it becomes symptomatic or life threatening. This raises the prospect of living a disease-free life, until the inevitable demands of the aging process lead to death at an advanced age. Yet this happy goal is achievable only if the pace and sophistication of research are increased.
The notion of preventive medicine at a personal level is in some respects antithetical to the traditional social contract between a physician trained in the Western tradition and his or her patient. The contract reads, in essence: "If you become sick, then I am available for help. If you are not ill, that is someone else's responsibility." It will be interesting to see how this doctor and "nonpatient" relation develops in the coming decades.
I would like to digress a moment from the discussion of prevention and talk briefly about therapeutic medicine. The science and art of medicine are dependent on accurate diagnosis. The physician attempts to sort patients into diagnostic categories or "bins." Once classified, the patient is assigned a prescribed pattern of therapy. Diagnosis will become more specific as the genetic and other etiologies of more and more symptom complexes become known. Instead of treating a patient as a member of a category, each patient will have his or her unique diagnosis and treatment. Oddly, this pattern is similar to the style of some non-Western indigenous medical systems in which individualized treatment is prescribed for each patient.
Currently, there are person-to-person differences in response to treatment, such as age and gender, that are known prior to the initiation of treatment and that influence treatment. With increased knowledge of the genome, more genes that influence response to drugs will be discovered and understood. The science of "pharmacogenetics" will make it possible to design therapy based on prior knowledge of the response expected.
Application of this genetic knowledge has and will raise many ethical questions, which can only be alluded to in this presentation. The organizers of the Genome Project have, wisely, included a study of actual and potential ethical problems as an integral part of the research project. This may be the first organized effort incorporated in a major research program to identify potential ethical issues before, or at the same time, that they arise. It can be said to be an anti-Frankenstein's monster program; a disaster-prevention strategy.
A goal of a program of identifying susceptibility genes would be to advise people at risk of the hazards, in order to mitigate them. The geneticist would also want to advise people who do not have the susceptibility genes that they