Gene variant may protect against severe COVID-19, scientists say
By Alexandra Mae Jones
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TORONTO (CTV Network) — Scientists believe they have identified a specific gene variant that may protect against severe COVID-19 infection, something they say could be key to developing new drugs to tackle the virus.
While we know that factors such as age and chronic conditions can increase the risk of severe cases of COVID-19, one of the lesser understood aspects of risk is genetics.
Previous studies have found that people who have a certain segment of DNA have a 20-per-cent lower risk of developing a critical case of COVID-19, according to a press release for this new study, but the problem is that this segment has many variants, making it hard to pinpoint what aspect of the DNA was having a protective effect. Specifically, it spans three genes: OAS1, OAS2 and OAS3.
This particular segment of DNA, which encodes genes in the immune system, is inherited from Neanderthals in around half of all people outside of Africa.
So how to narrow the segment of DNA down to a specific gene variant?
The previous studies had largely looked at individuals of European ancestry. In this new study, which was published Thursday in the journal Nature Genetics, researchers focused on individuals of African ancestry.
Because the inheritance of this DNA from Neanderthals occurred after the ancient migration out of Africa, those with African ancestry who lack that Neanderthal inheritance are lacking the majority of this specific DNA segment.
However, a small part of this DNA segment is found in both people of European and of African descent, meaning that if individuals of African ancestry with no Neanderthal connection were found to have this 20-per-cent lower risk of severe COVID-19, it could narrow down which part of the DNA might be providing this effect.
That was exactly what researchers found, the study revealed.
“The fact that individuals of African descent had the same protection allowed us to identify the unique variant in the DNA that actually protects from COVID-19 infection,” Jennifer Huffman, the first author of study and a researcher at the VA Boston Healthcare System, said in the release.
Researchers looked at 2,787 patients hospitalized with COVID-19 who were of African ancestry, as well as more than 130,000 people across six studies as a control group.
They found that 80 per cent of the 2,787 patients had the protective gene variant, which was compared to a previous metastudy of nearly 50,000 individuals of European ancestry to pinpoint the gene variant.
The protective gene variant, researchers say, is called rs10774671-6, and its main job is deciding the length of a protein encoded by the gene OAS1. When this protein is longer, it is better at breaking down SARS-CoV-2, the virus which causes COVID-19.
OAS1 itself plays a critical role in inhibiting viral replication and antiviral response. Previous research has suggested that specific genetic variations in the OAS1 gene could be linked to severe COVID-19, outlining how important it may be in determining risk.
Essentially, altering the splicing of OAS1 may be able to influence outcomes from COVID-19, making this something that could be targeted with future medication.
“That we are beginning to understand the genetic risk factors in detail is key to developing new drugs against COVID-19,” Brent Richards, co-author of the research and senior investigator at the Lady Davis Institute of the Jewish General Hospital and professor at McGill University, said in the release.
Researchers pointed out that this result highlights how it’s essential to study a diverse group of individuals in order to get a more clear picture, as studying only those of European descent would’ve made it much more difficult to narrow in on this gene variant.
“This study shows how important it is to include individuals of different ancestries,” Hugo Zeberg, assistant professor at the Department of Neuroscience at Karolinska Institutet and corresponding author of the study, said in the release. “If we had only studied one group, we would not have been successful in identifying the gene variant in this case.”
This is not the only research focusing in on how genes play a role in COVID-19 outcomes.
Polish scientists announced Thursday that they had found a gene that more than doubles the risk of becoming severely ill with COVID-19. The gene was found in a quarter of the population of India and around 14 per cent of the Polish population.
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Sonja Puzicsonja.puzic@bellmedia.ca
