Credit: Technology Review
BIOMEDICINE
Studies show that the genetic risk of disease varies between different ethnic groups, and data on some groups is lacking.
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.
People of African descent tend to have high levels of genetic diversity because of the population's long history. Genetic studies of disease have focused on people of European descent in part because it has historically been easier to study groups that are genetically similar and in part because much of this research is done in Europe and North America, where this group is the easiest to access.
More sophisticated methods for analyzing genetic data that have been developed over the last few years make it possible to study more diverse populations. Geneticists have discovered that this diversity can be helpful in narrowing down the particular genetic mutation linked to a disease. However, such studies require very large groups of people. "That's part of the reason we are aiming for 10,000 individuals just to get it started," says Joanna Mountain, senior director of research at 23andMe. In addition, cheaper DNA chips mean that studies of this size are more affordable.
The 23andMe project was inspired in part by the company's work with Henry Louis Gates, director of the W. E. B. Du Bois Institute for African and African American Research at Harvard University. Gates's PBS documentaries use genetics to help people explore their ancestry. "He had been encouraging us to reach out to African Americans," says Mountain. "But I pointed out that the genetic research results to date lack information for African Americans."
Participants in the 23andMe study will be asked to fill out surveys on their general health history and common conditions, such as diabetes, allergies, asthma, and headaches. Asthma and some forms of migraines are more common in African Americans.
Rick Kittles, an associate professor at the University of Illinois who is advising 23andMe on the project, says that mistrust of research still exists among African Americans, given the disturbing history of the Tuskegee syphilis study, in which African American men thought they were being treated for the disease but were not. "As African Americans and Hispanics see themselves more and more in research, that mistrust starts to ease," says Kittles, who is African American. "But it is utterly important to have underrepresented researchers like myself and others involved in these projects."
Unlike more traditional research studies, participants will get the results of their tests and the meaning of their own genetic variations. "Our goal is to keep participants engaged and excited about research by telling them what we discovered," says Mountain. The project is part of 23andMe's growing emphasis on participatory research. It recently published the first results of a study of Parkinson's disease that identified two new genetic risk factors.
"The 23andMe project is paradigm shifting in many ways," says Kittles. "It allows people to be more proactive in understanding their ancestry and their own health."
No comments:
Post a Comment