Stockholm:

Researchers have identified a specific gene variant that protects against severe covid-19 infection.

An international team led by researchers at Karolinska Institutet in Sweden pointed out the variant by studying people of different backgrounds.

The study, published in the journal Nature Genetics, shows that genes can affect whether we are severely affected or only suffer from mild covid-19 disease.

Previous studies on mainly people of European descent have found that individuals carrying a certain segment of DNA have a 20 percent lower risk of developing a critical covid-19 infection.

This DNA segment encodes genes in the immune system and is inherited from Neanderthals in about half of all people outside Africa, the researchers said.

But this DNA region is packed with many genetic variants, which makes it challenging to figure out the exact protection variant, they said.

Identifying this variant could potentially serve as a goal for medical treatment for severe COVID-19 infection, according to the researchers.

To identify this specific gene variant, they looked for individuals that carried only parts of this DNA segment.

Because the legacy of the Neanderthals occurred after the ancient migration out of Africa, the researchers focused on individuals of African descent who lack the legacy of the Neanderthals and therefore also the majority of this DNA segment.

However, a small part of this DNA region is the same in both people of African and European descent.

The researchers found that individuals of predominantly African descent had the same protection as those of European descent, which enabled them to identify a specific gene variant of particular interest.

“The fact that individuals of African descent had the same protection enabled us to identify the unique variant in the DNA that actually protects against COVID-19 infection,” said the first author of the study, Jennifer Huffman, a researcher at VA Boston Healthcare System in the United States.

The analysis included a total of 2,787 admitted covid-19 patients of African descent and 130,997 people in a control group from six cohort studies.

Eighty percent of individuals of African descent wore the protective variant, the researchers said.

The results were compared with a previous, larger study of individuals of European heritage.

According to the researchers, the protective gene variant (rs10774671-G) determines the length of the protein encoded by the gene OAS1.

Previous studies have shown that the longer variant of the protein is more effective in breaking down SARS-CoV-2, the virus that causes COVID-19.

“Getting to understand the genetic risk factors in detail is key to developing new drugs against COVID-19,” said study co-author Brent Richards, a professor at McGill University in Canada.

(Apart from the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)