Scientists in the UK have identified some genetic factors that make certain people suffer severe symptoms from COVID-19 than others, a finding that could help develop more effective treatments for the viral disease.

The team led by researchers from the University of Edinburgh in the UK in partnership with Genomics England sequenced the genomes of 7,491 patients from 224 intensive care units in the UK. Their DNA was compared with 48,400 other people who had not had COVID-19, and that of a further 1,630 people who had experienced the mild disease.

Determining the whole genome sequence for all participants in the study allowed the team to create a precise map and identify genetic variation linked to the severity of COVID-19. The team found key differences in 16 genes in the ICU patients when compared with the DNA of the other groups.

"Our latest results explain why some people develop life-threatening COVID-19, while others get no symptoms at all," said Professor Kenneth Baillie, a consultant in critical care medicine at the University of Edinburgh. "However, more importantly, this gives us a deep understanding of the process of disease and is a big step forward in finding more effective treatments," Baillie said.

The researchers also confirmed the involvement of seven other genetic variations already associated with severe COVID-19 discovered in earlier studies from the same team. The findings included how a single gene variant that disrupts a key messenger molecule in immune system signalling -- called interferon Alpha-10 -- was enough to increase a patient's risk of severe disease.

This highlights the gene's key role in the immune system and suggests that treating patients with interferon -- proteins released by immune cells to defend against viruses -- may help manage disease in the early stages. The study also found that variations in genes that control the levels of a central component of blood clotting -- known as Factor 8 -- were associated with critical illness in COVID-19.

This may explain some of the clotting abnormalities that are seen in severe cases of COVID-19, the researchers said. Factor 8 is the gene underlying the most common type of haemophilia, they said. "Through our whole-genome sequencing research, we have discovered novel gene variants that predispose people to severe illness -- which now offer a route to new tests and treatments, to help protect the public from this virus," said Professor Mark Caulfield from Queen Mary University of London, and co-author of the study

Rich Scott, Chief Medical Officer at Genomics England, noted that strategically, genomic science is becoming an integral part of the national infrastructure in routine healthcare. "It represents a major leap forward in our understanding of how our genetic makeup influences severe illness with COVID-19," Scott added.