Faulty gene linked to dementia ‘doubles the risk of severe Covid-19’

People with a faulty gene linked to dementia may be twice as likely to exhibit severe coronavirus symptoms, new research indicates.

Scientists have said the ApoE4 gene, found in people of European ancestry, is linked to a greater risk of severe Covid-19, even when they were not affected by dementia.

The findings, published in the Journal of Gerontology: Medical Sciences, suggest that some people may be genetically predisposed to be more severely affected by the strain sweeping the world.

However Alzheimer’s Research UK​ said the study should be interpreted with caution and more research is needed.

Study leader David Melzer, a professor of epidemiology and public health at Exeter University, said: “Several studies have now shown that people with dementia are at high risk of developing severe Covid-19.

“This study suggests that this high risk may not simply be due to the effects of dementia, advancing age or frailty, or exposure to the virus in care homes."

He added: “The effect could be partly due to this underlying genetic change, which puts them at risk for both Covid-19 and dementia.”

Data from 500,000 people was analysed for the study which was collected by UK Biobank.

Scientists found those who carry two faulty copies of the ApoE4 gene are at double the risk of being severely affected by Covid-19 infection than those who do not have this genetic mutation.

One in 36 people of European ancestry are thought to have two faulty copies of this gene.

Study co-author Dr Chia-Ling Kuo, of the University of Connecticut School of Medicine in the US, said: “This is an exciting result because we might now be able to pinpoint how this faulty gene causes vulnerability to Covid-19. This could lead to new ideas for treatments.”

However, Dr Carol Routledge, director of research at Alzheimer’s Research UK, urged caution when interpreting these findings.

Commenting on the research, Dr Routledge, who was not involved in the study, said: “We don’t yet know how this Alzheimer’s risk gene might make people more susceptible to the virus.

“Despite the large study group, only 37 people with the risk gene tested positive for Covid-19, and we must be careful about the conclusions we draw from such small numbers.

“These findings will need to be followed up with further research to see if this link could present avenues for new treatments.”

Prof Tara Spires-Jones, deputy director at the Centre for Discovery Brain Sciences at the University of Edinburgh, added: “An important limitation of the current paper is that this type of observational study cannot prove that the ApoE4 gene is the cause of the observed increased risk of Covid-19.

“The scientists did a thorough job of trying to control for other things associated with ApoE4 that could account for the risk, but it is still possible that there is an unknown related factor causing the increased risk.”