Genetic risk factors for disease can be affected by environment

Genetic differences in immune response show an interaction between genetics and the environment that can be linked to disease risk.
By Amy Wallace   |   Aug. 16, 2017 at 5:00 AM
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Aug. 16 (UPI) -- A team of U.S. and German researchers has found that genetic variants affect how much gene expression changes in response to disease.

The study, published today in Nature Communications, involved researchers analyzing blood from 134 volunteers, and treated monocytes, or white blood cells, in the laboratory with three components to simulate infection with bacteria or virus.

"Our defense mechanisms against microbial pathogens rely on white blood cells that are specialized to detect infection. Upon encounter of microbes, these cells trigger cellular defense programs via activating and repressing the expression of hundreds of genes," said Dr. Veit Hornung of the Ludwig-Maxmilians-Universität in Munich, formerly from the University of Bonn.

Researchers analyzed how cells from different individuals respond to infection by measuring gene expression during the early and late immune response.

"It's been known for a long time that most diseases have both genetic and environmental risk factors," Dr. Tuuli Lappalainen of the New York Genome Center said in a news release.

"But it's actually more complicated than that because genes and environment interact. As demonstrated in our study, a genetic risk factor may manifest only in certain environments. We are still in early stages of understanding the interplay of genetics and environment, but our results indicate that this is a key component of human biology and disease. The molecular approach that we took in our study can be a particularly powerful way for researchers to delve deeper into this question."

The study identified genetic variants whose effects on gene regulation differed depending on the various infectious state of cells. Some of the variants included four associations to diseases such as cholesterol level and celiac disease.

Researchers also discovered a tendency in genetic risk for autoimmune diseases such as lupus and celiac disease to be enriched for gene regulatory effects altered by the immune state.

The results of the study identified population differences in immune response and showed that immune response changes genetic associations to diseases.

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