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The deepening importance of diversity
According to a new study published in Nature, researchers have identified 27 new genomic variants associated with conditions such as blood pressure, type 2 diabetes, cigarette use and chronic kidney disease in diverse populations. The team collected data from 49,839 African American, Hispanic/Latinx, Asian, Native Hawaiian, Native American and others who did not identify as part of those specific ethnic groups.
The study’s purpose was to better understand how genomic variants influence the risk of forming certain diseases in people of different races and ethnic groups. The work was funded by the National Human Genome Research Institute (NHGRI) and the National Institute on Minority Health and Health Disparities, both parts of the National Institutes of Health (NIH).
In this study, researchers specifically looked for genomic variants in DNA that were associated with measures of health and disease. The team found that some genomic variants are specifically found in certain groups. Others, such as some related to the function of hemoglobin, are found in multiple groups.
“There are scientific benefits to including people from different ethnic groups in research studies. This paper gives us a glimpse of how ethnic diversity can be harnessed to better understand disease biology and clinical implications. This paper represents an important comprehensive effort to incorporate diversity into large-scale studies, from study design to data analysis,” said Lucia Hindorff, Ph.D., program director in the Division of Genomic Medicine at NHGRI and a co-author of the paper.
As well as finding new genomic variants, the study assessed whether known disease associations with 8,979 established genomic variants and specific diseases in white European ancestry populations could be detected in African American, Hispanic/Latinx, Asian, Native Hawaiian and Native American populations. Their findings show that the frequency of genomic variants associated with certain diseases can differ from one group to another.
For example, a strong association was found between a new genomic variant and smokers’ daily cigarette usage in Native Hawaiian participants. This association was absent or rare in most other populations. Not finding the variant in all groups despite large numbers of participants in each group strengthens the argument that findings from one population cannot always be generalized to others.
A variant in the hemoglobin gene, a gene known for its role in sickle cell anemia, is associated with greater amount of blood glucose attached to hemoglobin in African Americans. The paper in Nature is the first to confirm this association within Hispanic/Latinxs, who have shared ancestry that is mixed with European, African and Native American ancestry.
This effort is vital because a vast majority of human genomics research use data based mostly on populations of white European ancestry. For example, a separate study showed that among 2,500 recently published human genomics papers, only 19% of the individuals studied were people of color.
The inclusion of diverse populations in studies is incredibly important. Ethnicity may partly explain the differences in vulnerability to diseases and treatment effects. This is because there could be genomic variants present in other ethnic populations that increase the risk for diseases, but they will not be found if studies are only done with white participants. Using genomic data from only white populations to extrapolate to other populations will not accurately predict the disease burden carried by such groups.
“Ultimately, the PAGE study underscores the value of studying diverse populations, because only with a full understanding of genomic variations across populations can researchers comprehend the full potential of the human genome,” Hindorff added.
This work is a benchmark that addresses the need for new methods and tools for collecting and disseminating large and varied amounts of genomic data, in order to make the results clinically useful. The study is part of the Population Architecture using Genomics and Epidemiology (PAGE) consortium formed in 2008, comprising researchers at NHGRI and centers across the United States. The Nature paper on the study, which was led by researchers at the Icahn School of Medicine at Mount Sinai, the Fred Hutchinson Cancer Research Center and other academic centers, is the result of work undertaken by the consortium in the last five years.
Through PAGE and subsequent studies, researchers will be able to identify genomic variants that are associated with diseases from those that are not. They will also be able to identify how such associations differ across race and ethnicity. In turn, this improved understanding can be used to target and tailor new treatments to maximize the benefits across all populations.