Study of multiethnic genomes identifies 27 genetic variants associated with disease

June 21, 2019

According to a news release, in a study published in the journal Nature, researchers 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/Latino, Asian, Native Hawaiian, Native American, and people who identified as others and were not defined by those ethnic groups. The study aimed to better understand how genomic variants influence the risk of forming certain diseases in people of different 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 NIH.

In this study, researchers specifically looked for genomic variants in DNA that were associated with measures of health and disease. Everyone has DNA sequences that consist of the chemical bases A, C, G, T. Genomic variants occur in DNA regions where one of those bases is replaced with another, across various individuals. The team found that some genomic variants are specifically found in certain groups. Others, such as some related to the function of hemoglobin (a protein in the blood that carries oxygen), are found in multiple groups.

Apart from finding new genomic variants, the study assessed whether known disease associations with 8,979 established genomic variants and specific diseases in European ancestry populations could be detected in African American, Hispanic/Latino, 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 and their daily cigarette usage in Native Hawaiian participants. However, 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/Latinos, who have shared ancestry that is mixed with European, African and Native American ancestry.

Such an 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 percent of the individuals studied were non-European participants.

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