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ScienceWeek
GENOMICS AND GLOBAL HEALTH
The following points are made by David J. Weatherall (Science 2003 302:597):
1) The announcements of the partial completion of the human and some of the pathogen genome projects were accompanied by promises that these remarkable achievements would lead to a complete revolution in medical practice over the next 20 years; many of our intractable killers would become preventable, and those that are not would be controlled by new families of medicines derived from knowledge of our genetic make-up, or those of our pathogens (1–3). Only 2 years later, and as we celebrate the 50th anniversary of the discovery of the structure of DNA, it is becoming clear that some of these promises were premature.
2) Most of these pronouncements related to the common diseases of the richer countries, which are likely to be the result of variable susceptibility mediated through many different genes, the action of rapidly changing environmental agents, and the complex and ill-understood pathology of aging. As we enter the new millennium, even these complexities pale into insignificance compared with the health problems of the developing world: four million children lost each year from infectious diseases for which vaccines or other forms of prevention are already available; 70% of the 40 million people with HIV/AIDS infection concentrated in countries with completely dysfunctional health care systems; and millions dying each year because of poor sanitation, unsafe water, and air pollution, not to mention a lack of basic health care (4,5).
3) Nor are the problems of the poorer countries restricted to the effects of communicable disease and poverty. As social and environmental conditions improve, many countries pass through the epidemiological transition from infectious to noncommunicable disease. Globally, heart disease is now the commonest killer, and late-onset diabetes and obesity are emerging as a new pandemic; it is estimated that there are 150 million affected people worldwide, and that number is expected to double by 2025. In some poorer populations, the rate of stroke is already four to five times that in richer countries. To make matters worse, in many countries that are going through this epidemiological transition, infectious disease has not yet been controlled.
4) Considering the magnitude of these problems, it is not surprising that the major international health agencies have made the reduction of known or perceived risk factors for both communicable and noncommunicable disease their main priority for the immediate future (4). Genomics research and its immediate applications do not appear anywhere on their agenda.
5) In summary: Although currently there are only a limited number of genomic technologies that are applicable to health care in the developing countries, this is unlikely to be the case in the near future. If, however, the full potential of genomics for health care is to be fulfilled, there will have to be a complete change of emphasis in education and research in the richer countries toward a more global view of disease and its consequences.
References (abridged):
1. F. S. Collins, V. A. McKusick, JAMA 285, 540 (2001)
2. G. Subramanian, M. D. Adams, J. C. Venter, S. Broder, JAMA 286, 2296 (2001)
3. F. S. Collins, E. D. Green, A. E. Guttmacher, M. S. Guyer, Nature 422, 835 (2003)
4. World Health Report, 2002 (World Health Organization, Geneva, 2002)
5. 2002 World Development Indicators (World Bank, Washington, 2002)
Science http://www.sciencemag.org
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DEFINING DISEASES IN THE GENOMICS ERA
The following points are made by L.K.F. Temple et al (Science 2001 293:807):
1) The human genome sequence will dramatically alter how we define, prevent, and treat disease. As more and more genetic variations among individuals are discovered, there will be a rush to label many of these variations as disease-associated.
2) The authors suggest we need to define the term "disease" so that it incorporates our expanding genetic knowledge, taking into account the possible risks and adverse consequences associated with certain genetic variations, while acknowledging that a definition of disease cannot be based solely on one genetic abnormality.
3) The authors point out that the human genetic sequence is likely to reveal many harmless genetic variations that will turn out not to be associated with disease. Disease is a fluid concept influenced by societal and cultural attitudes that change with time and in response to new scientific and medical discoveries. Until we resolve questions about polymorphisms, incomplete penetrance of genetic mutations, and the contribution of environmental factors to disease etiology, we will not be able to assess the probability of adverse consequences associated with a particular gene abnormality. Until a mutation is demonstrated to involve a defined risk of developing adverse consequences, individuals carrying that mutation should not be considered diseased.
Science http://www.sciencemag.org
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