Study identifies 27 genetic variants associated with disease in multiethnic genome

A recent study has identified 27 new genomic variants associated with conditions such as blood pressure, type II diabetes, cigarette use and chronic kidney disease in diverse populations.

The study, which aimed to better understand how genomic variants influence the risk of forming certain diseases in people of different ethnic groups, was published in the journal 'Nature'.

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.

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 haemoglobin (a protein in the blood that carries oxygen), are found in multiple groups.

The study gives a glimpse of how ethnic diversity can be harnessed to better understand disease biology and clinical implications.

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 showed 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 generalised to others.

A variant in the haemoglobin gene, a gene known for its role in sickle cell anemia, is associated with a greater amount of blood glucose attached to hemoglobin in African-Americans.

Inclusion of non-European populations in studies is important because ethnicity may partly explain the differences in vulnerability to diseases and treatment effects.

This is because there may be genomic variants present in other ethnic populations that increase the risk for diseases, but they would not be found if studies were only done on white European populations. Using genomic data from white Europeans to extrapolate to other populations may not accurately predict the disease burden carried by such groups.

The study is part of the Population Architecture using Genomics and Epidemiology (PAGE) consortium, which was formed in 2008, comprising researchers at NHGRI and centers across the United States.

"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," said Lucia Hindorff, a co-author of the study.