Nicholas Weiler, Medical Xpress, May 12, 2016

Results from the largest single study of the genetic and environmental causes of asthma in African-American children suggest that only a tiny fraction of known genetic risk factors for the disease apply to this population, raising concerns for clinicians and scientists working to stem the asthma epidemic among African-Americans.

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“Almost all the genetic studies of asthma have been done using white patients only, but you can’t assume these results will apply to other ethnic groups,” said study senior author Esteban Burchard, MD, MPH, a professor in the UCSF Schools of Pharmacy and Medicine, director of the UCSF Asthma Collaboratory lab and a member of President Obama’s Precision Medicine Initiative. “This paper is an important first step towards truly understanding the biology of asthma in African-Americans.”

More work remains to confirm whether the genetic risk factors for asthma identified in previous studies are truly absent in African-Americans or merely too subtle to be detected in the current study, the authors say, but the results clearly show the biology of asthma is different black children and previously studied groups.

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“This paper shows that understanding that people are different–not better or worse, equal or unequal, but different at a genetic level–can be important and should be looked at to improve health,” said Risse-Adams, now a sophomore at Lowell.

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The study led by White and Risse-Adams analyzed genetic data from 1,227 SAGE participants–812 with asthma and 415 who served as healthy controls–to identify genetic markers associated with the onset of the disease in African-Americans and to compare these markers with those already known from previous research. The team also looked for possible genetic links between asthma and obesity, which often occur together.

To the researchers’ surprise, 95 percent of known genetic risk factors for asthma from previous research could not be replicated in the SAGE cohort.

The team also identified a number of new risk factors in the African-American children of the SAGE study, including a novel variant in the PTCHD3 gene, as significant risk factors for asthma.

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U.S. Childhood Asthma Rates

Breakdown of prevalence by racial/ethnic population:

18.4% Puerto Rican

14.6% African-American

8.2% White

4.8% Mexican