Stanford geneticist Carlos Bustamante, PhD, is the lead author of a commentary in Nature Medicine today describing a significant stumbling block in the effort to identify genetic variations linked to common disorders. From the article (subscription required):
In the past decade, researchers have dramatically improved our understanding of the genetic basis of complex chronic diseases, such as Alzheimer's disease and type 2 diabetes, through more than 1,000 genome-wide association studies (GWAS). These scan the genomes of thousands of people for known genetic variants, to find out which are associated with a particular condition.
Yet the findings from such studies are likely to have less relevance than was previously thought for the world's population as a whole. Ninety-six percent of subjects included in the GWAS conducted so far are people of European descent. [...] And a recent Nature survey suggests that this bias is likely to persist in the upcoming efforts to sequence people's entire genomes.
This sampling bias might not matter much if it weren't for the fact that Bustamante's recent work has shown that the prevalence of rare mutations can vary significantly among human populations. Because it's seeming more and more like these rare variants may play a significant role in disease development and in how a person responds to specific medications, it's becoming clear that a cookie-cutter approach to genetics and health may not work. The authors, who include Stanford visiting scholar Francisco de la Vega and UC San Francisco's Esteban Burchard, MD, conclude:
It is tempting to focus on populations that are motivated, organized, medically compliant and otherwise easy to study. But by failing to develop resources, methodologies and incentives for underserved people, we risk perpetuating the health disparities that plague the medical system. Those most in need must not be the last to receive the benefits of genetic research.
Ways to increase representation of underserved populations include fostering collaboration between developed and developing countries, empowering physicians and scientists in developing countries to conduct research that will benefit their local communities, and helping peer reviewers and granting agency understand the importance of racial and ethnic diversity in medical genetic studies.
Previously: Roots of disease may vary with ancestry, according to Stanford geneticist and Stanford geneticist Carlos Bustamante named a MacArthur fellow
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