Air Date: Week of July 25, 1997

Human disease can often be chalked up to both our genes and the environment. But, just how these two factors conspire with each other is poorly understood. The National Institute of Environmental Health Sciences wants to shed light on that complex interplay through a new effort dubbed the Environmental Genome Project. A Human Genome Project is already underway, searching for location and function of genes. But, this new research will try to match known genes with exposures to toxins and disease. From Chapel Hill, North Carolina, Diane Toomey has this report.

Transcript

KNOY: Human disease can often be chalked up to both our genes and the environment. But just how these 2 factors conspire with each other is poorly understood. The National Institute of Environmental Health Sciences wants to unravel that complex interplay through a new effort dubbed the Environmental Genome Project. A human genome project is already underway, searching for location and function of genes. But this new research will try to match known genes with exposures to toxins and disease. From Chapel Hill, North Carolina, Diane Toomey has this report.

TOOMEY: Why do some of us develop cancer, asthma, or other conditions often linked to environmental toxins, while others escape unscathed? Part of the answer may lie in the chemical building blocks of our genes, and the normal genetic differences among people. The problem is right now, we don't know which genetic variations make us more vulnerable to toxins, or even which toxins trigger these genes. But Ken Olden wants to find out. He's the director of the National Institute of Environmental Health Sciences. Dr. Olden says this knowledge gap prevents us from going after the pollutants that do the most harm.

OLDEN: Right now I think we don't have a good way to set our priorities. Just because one chemical is very high in the environment and another one's very low, it doesn't mean that the one that's very low is not causing more harm. And I think if we really know the bad actors, based on the genetics of the American population, then we could focus on those that cause the devastating diseases and clean those up first.

TOOMEY: The Environmental Genome project will try to identify who those bad actors are. It will set its sights on 200 genes believed to play a role in environmentally-induced disease, like genes known to work in the liver to detoxify blood and those that repair DNA. Researcher Jack Taylor.

TAYLOR: There are plenty of gene candidates out there for us to look at, and then sequence them in some number of individuals to identify all the different variants that we can find.

TOOMEY: Gene variants are the normal varieties of a given gene. For example, everyone has genes for eye color, but people with blue eyes have slightly different genes than those with brown. Similarly, some varieties of genes protect us against toxins, while others leave us more vulnerable. And according to Jack Taylor, all of us probably have a number of genes that put us at risk.

TAYLOR: For example, in bladder cancer, we've been looking at a gene called glutathianous transferase, which is a gene that's responsible for detoxifying some of the carcinogens in tobacco smoke. And about 50% of Caucasians are totally deficient in that gene. They don't have a working copy of the gene at all.

TOOMEY: The Environmental Genome Project will try to identify more of these common problem genes and chemical culprits by comparing disease rates in people with different versions of the same relevant gene and similar exposures to environmental triggers. NIEHS Director Ken Olden says the results could have far-reaching implications.

OLDEN: You can imagine if 50% of the population have a genetic defect or mutation that make them more susceptible to a specific environmental exposure, then if we knew that, then the impact that that information can have on public health is tremendous.

TOOMEY: But there are those who caution against over-selling the Environmental Genome Project. George Gray, Deputy Director of Harvard's Center for Risk Analysis, is one of them. He points out that scientists will only make an educated guess about which 200 genes to analyze, a process that will take an estimated 3 years and $60 million to complete.

GRAY: At this point it's exploratory and hypothesis-generating, and we have to be careful about portraying it as sequencing genes that we know are important.

TOOMEY: And, he adds, it's not clear how predictive the project's early findings might be.

GRAY: So that even if we can draw a relationship between one of these genes and an environmentally-induced disease, it's extremely unlikely to be a direct one to one, if you have this genetic variant you will get this disease. It just won't happen. We have to be careful about how we portray this because of its potential for raising both unrealistic hopes and unfounded fears in the public.

TOOMEY: And critics and researchers alike have another concern. The findings might not be used to protect the public health but to discriminate against individuals or even entire ethnic groups. Karen Rothenberg is the director of the Law and Health Care Program at the University of Maryland.

ROTHENBERG: What we wouldn't want to happen was for there to be an incentive where employers could pick and choose ahead of time which employees they would want, when really what they should be doing is cleaning up the workplace, so that they can protect all employees whether or not they have higher levels of susceptibility.

TOOMEY: Although a Federal law bans genetic discrimination against employees in group health plans, there are no Federal laws that protect the privacy of a person's genetic test results. The Equal Employment Opportunity Commission has said the Americans with Disabilities Act would protect workers from genetic discrimination on the job. But that protection has never been tested in court. Still, critics allow the project could eventually provide valuable public health information. And Stanford University geneticist David Cox says the project's potential benefits go beyond science. Dr. Cox sits on the President's National Bioethics Advisory Commission and says this research may spark some much-needed public debate.

COX: One thing that I think I'm most excited about, about this Environmental Genome Project, is that it's going to be an opportunity for the scientists, for the policy makers, and for the public, for the unions, for the employers, to all work together to figure out the best way to bring genetic environmental information together to improve people's lives.

TOOMEY: Dr. Cox says that will be the hardest part: making the Environmental Genome Project pay off for society. For Living on Earth, I'm Diane Toomey.