Why some coronavirus patients fare worse than others could be answered by analysing their DNA to pinpoint any genetic variations. A major study involving thousands of UK patients who have fallen ill with coronavirus will have their genomes read to try and understand how their DNA affects their susceptibility to the infection.

The UK-wide effort aims to collect DNA samples from up to 20,000 Covid-19 patients currently or previously in intensive care units, along with 15,000 more from patients who had mild or moderate symptoms. Doctors intend to gather DNA from patients in 170 intensive care units and ultimately aim to collect genetic samples from all Covid-19 patients admitted to intensive care in the UK, provided they give consent. Nearly 2000 Covid-19 patients have already donated DNA for the £28 million study, run by Edinburgh University and multiple NHS hospitals. The work is backed by the UK government, Genomics England and the Genetics of Mortality in Critical Care consortium of researchers.

Doctors hope that analysing these patients’ DNA will reveal genetic variations that affect the course of the infection in different people. The hope is that this might potentially point to specific drugs that patients could benefit from.

Kenneth Baillie, a Consultant in Critical Care Medicine at Edinburgh University and Chief Investigator on the study, said genes are believed to play a role in determining which patients become desperately sick from Covid-19 and which recover more swiftly. Understanding which genes are most important, and how they interact with the infection, could help fast-track experimental drugs into clinical trials, he said.

Genetics may have the answer

In the UK, men are dying of coronavirus at twice the rate of women. Genetics may shed light on why this may be and why some people who are otherwise healthy die from the disease. Doctors will also be keen to see whether genes play a role in a rare, but serious, inflammatory response in children that appears to be triggered by coronavirus. At least six countries have now reported cases of children becoming seriously ill with a condition that resembles a mix of toxic shock and Kawasaki disease, which can lead to inflammation of the heart.

“It’s becoming increasingly likely that a person’s genetic makeup plays a big role in susceptibility in terms of how effectively they can mount an immune response, and how durable that immunity is”, said David Bentley, Chief Scientist at Illumina, the biotech firm that will read the whole genome sequences of patients enrolled in the study. “We already know one route of entry of the virus into human cells and this is subject to genetic variation, just as was the case in HIV infection.”

Sue Hill, Chief Scientific Officer for Genomics at NHS England, said the study had the potential to dramatically improve our understanding of Covid-19.

“It could help us to identify whether underlying genomic differences play a part in how people react to the virus and why some people have few or no symptoms, while others can get very ill”, she said.

Other research teams are also looking at whether DNA testing can help Covid-19 patient care.

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