Genetic screening may redefine medical treatments


Doctor's office visits are the norm for 9-year-old Shamatay Hayes. She was diagnosed with asthma at age 2, something she and her mom have struggled to keep under control.

"It is challenging," her mother says.

At San Francisco General Hospital and at asthma clinic across the country, Shamatay's lung function is tracked using standard benchmarks such as age, gender and race. But, researchers say there is now a better way.

"So, what we can now do with modern techniques is estimate what a person's ancestry is or what their heritage is using a series of genetic markers," says UCSF researcher Dr. Melinda Aldrich.

The genetic markers more accurately determine lung function rather than a patient's self-identification as simply white, black or Hispanic.

"With increasing African ancestry, we saw a decrement in lung function," says UCSF associate professor Dr. Esteban Burchar.

Burchard is director of UCSF's Center for Genes, Environment and Health, and senior author of a paper just published in the New England Journal of Medicine.

"We said forget what you think you are, what people think you are, and we looked at your genetic ancestry. We were able to reclassify patients more accurately than just using self-identified criteria," explains.

That is increasingly important because race is used to establish normal reference values for everything from diagnosing disease to establishing disability payments. For instance, a mixed-race firefighter who suffers smoke inhalation might not meet the standards for disability of what is considered normal lung function since that is based on just three racial categories right now.

"What we showed is when you use these race-based standards, you could have as much as a 10 percent error rate depending upon what your true ancestry," Burchard says.

Burchard believes this research brings us closer to truly-personalized medicine, but he is also aware of the potential controversy.

"We've had people contact us who were supremacists that said you know what you're doing is validating what we believe," he says.

But, the research actually tells a different story.

"Most of us, all of us in fact, are racially mixed," he says. "We have a very rich heritage and what we're doing is acknowledging that mixture and incorporating it into our clinical assessments."

Scientists believe their results on lung function are just the beginning.

Aldrich says, "Wherever potentially we use race now for making medical decisions, it may have an impact with other diseases."

This would ultimately make medicine more effective for everyone. The genetic tests used by researchers at UCSF cost about $10 per patient. Scientists see it as a small price to pay for a more accurate assessment of disease, which could lead to more effective treatments for patients.

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