Five genes common to victims of worst Covid

Scottish scientists have discovered people suffering the most severe form of coronavirus have five specific genes.

Doctor Jesse Erasmus checks vero cells as he works on the development of a replicon, or replicating, RNA vaccine, used to combat COVID-19 (SARS-CoV-2). Picture: AFP

Scottish scientists have discovered people suffering the most severe form of coronavirus have five specific genes, leading to identification of new repurposed drugs to treat patients.

The scientists, who used input from two Australians, believe this breakthrough will help diagnose those who may be more susceptible to serious illness and also help repurpose existing drugs that target the actions of the five genes.

The research, published in Nature, was conducted by the University of Edinburgh, assisted by the GenOMICC consortium, a global collaboration to study genetics in critical illness, including Yang Wu from the Institute for Molecular Bioscience, at the University of Queensland, and Alistair Nichol from the Australian and New Zealand Intensive Care Research Centre at Monash University.

The study looked at the genes involved in antiviral immunity and lung inflammation to understand how COVID-19 damages lungs at a molecular level.

Scientists investigated the DNA of 2700 patients — 1574 males, 670 females and across a mix of European, Asian and African ancestries suffering coronavirus in 208 ICUs in Britain.

They found key differences in five genes of the ICU patients compared with samples provided by healthy volunteers. Scientists say the genes partially explain why some people become desperately sick with COVID-19, while others are not affected.

“This is a stunning realisation of the promise of human genetics to help understand critical illness,’’ said chief investigator Dr Kenneth Baillie from University of Edinburgh’s Roslin Institute.

“Just like in sepsis and influenza, in COVID-19, damage to the lungs is caused by our own immune system, rather than the virus itself. Our genetic results provide a road map through the complexity of immune signals, showing the route to key drug targets.”

Having identified the genes the scientists then predicted the effect of drug treatments, because some genetic variants respond in a similar way to particular drugs.

They said a reduction in the activity of the TYK2 gene protects against COVID-19 and that a class of anti-inflammatory drugs called JAK inhibitors, which includes the drug baricitinib, produces this effect.

Dr Baillie said: “Our results immediately highlight which drugs should be at the top of the list for clinical testing. We can only test a few drugs at a time, so making the right choices will save thousands of lives.’’