To date, research into the genetic cause of disease has been overwhelmingly white.
Of the participants in the most common type of genetic disease study, 96 percent are of European descent. Growing evidence suggests that the results of these studies, which encompass hundreds of thousands of people, may be less relevant or even irrelevant to those in other ethnic groups.
23andMe, a direct-to-consumer genetic testing company, aims to shift the balance. It will offer free testing to 10,000 African Americans as part of a research initiative to expand the diversity of its genetic database. The company hopes the project, announced last week at the National Urban League conference in Boston, will shed light on the genetic basis of disease in this population. More than 1,000 people have signed up on the website in the week since the project was announced.
A major motivation behind these genetic studies is to promote personalized medicine, which is aimed at predicting disease risk and treating patients based on their genetics. Experts worry that non-European ethnic groups will miss out on this new frontier if they are not included in such research. In addition to the 23andMe effort, several large-scale genetic projects on nonwhites are now underway.
Last year, the Carlos Slim Health Institute, a nonprofit based in Mexico City, and the Broad Institute, a genomics research institute in Cambridge, Massachusetts, launched a project to study the genetic basis of type 2 diabetes in Mexican and Latin American populations, as well as the genomics of cancer worldwide. In 2008, the National Institutes of Health opened a center devoted to the study of genetics, lifestyle, and disease in minority groups.
23andMe analyzes DNA using chips designed to detect a million common genetic variations across the genome. Users, who order the test online for $99, get a customized report detailing their genetic risk for about 200 diseases and other traits. The vast majority of predictions are based on studies that were mainly of people of European descent. So it’s not clear whether the findings are relevant for African Americans.
Research on a handful of diseases that have been studied across different ethnicities has shown that the genetic variants that increase risk often vary by population. Recent studies of asthma and prostate cancer, for example, have identified new disease-linked variations unique to those of African descent. Dozens of studies of Europeans have identified 19 common genetic variations linked to type 2 diabetes. But follow-up studies in a more diverse group found that five of those variations have different effects in different populations.