OCT 11, 2021 8:47 AM PDT

A Genetic Risk Factor is Shared by Alzheimer's and Severe COVID-19

WRITTEN BY: Carmen Leitch

While amyloid plaques are a hallmark of Alzheimer's disease, the neurological disorder has also been linked to inflammation and viral infections. Now, researchers have identified a genetic risk factor that is common to both Alzheimer’s disease and severe COVID-19. Small changes in the sequence of a gene called OAS1 can increase a person's risk of developing Alzheimer's, while related variations in the same gene can raise the chances of a serious case of COVID-19. The work, which has been reported in Brain, could help scientists develop new treatments for both disorders, and potentially, other causes of dementia.

Colorized scanning electron micrograph of chronically infected and partially lysed cells (blue) infected with a variant strain of SARS-CoV-2 virus particles (green), isolated from a patient sample. Image captured at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. / Credit: NIAID

The researchers noted that during a COVID-19 infection, inflammation may occur in the brain. This study has found a gene that could be increasing brain inflammation by exaggerating the immune system's response to COVID-19, said lead study author Dr. Dervis Salih of the UCL Queen Square Institute of Neurology and UK Dementia Research Institute at UCL. “We have found that some of the same immune system changes can occur in both Alzheimer’s disease and COVID-19."

The OAS1 gene is active in a type of brain cell called microglia. These cells are known to be involved in immunity in the brain, and are thought to make up about 10 percent of all the brain's cells.

In this study, the researchers assessed genetic sequence data from 2,547 people; half of these individuals had Alzheimer’s disease. One specific gene variant in OAS1 that's known as rs1131454 increased a person's likelihood of developing Alzheimer’s disease anywhere from 11 to 22 percent compared to people that did not carry the variant. This variant is common in Europeans; about half of them are thought to carry it, and its impact on Alzheimer's is more significant than several other known risk genes.

The four variants that the study focused on all decrease the OAS1 gene's activity. The study also determined that the variants that increase Alzheimer's risk are usually inherited together. The OAS1 variants can raise a person's chances of a severe COVID-19 case if they are infected with SARS-CoV-2 by as much as 20 percent.

Additional work suggested that when OAS1 is less active in microglia than normal, there is a heightened response to tissue damage, and the immune system turns on the body and attacks its own tissue. In this case, that autoimmune dysfunction would be occuring in the brain, with serious consequences.

The expression of OAS1 changes over a person's lifetime, so this work could also help explain why older people are more vulnerable to COVID-19 and other disorders including Alzheimer’s.

“If we could develop a simple way of testing for these genetic variants when someone tests positive for COVID-19, then it might be possible to identify who is at greater risk of needing critical care, but there is plenty more work to be done to get us there. Similarly, we hope that our research could feed into the development of a blood test to identify whether someone is at risk of developing Alzheimer’s before they show memory problems," Salih noted.

Sources: University College London (UCL), Brain

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 29, 2021
Cell & Molecular Biology
Study Suggests Cell Reprogramming Can Repair Heart Attack Damage
SEP 29, 2021
Study Suggests Cell Reprogramming Can Repair Heart Attack Damage
Cells carry the genome in their nucleus, and the genes that are expressed give a cell its identity. Researchers have bee ...
OCT 25, 2021
Microbiology
Bacteria Easily Share Mobile Genetic Elements That Confer Resistance to Phages
OCT 25, 2021
Bacteria Easily Share Mobile Genetic Elements That Confer Resistance to Phages
Microbes are engaged in a never-ending battle, and they have ways of attacking each other as well as defense mechanisms.
NOV 04, 2021
Microbiology
Investigating the Gut Virome
NOV 04, 2021
Investigating the Gut Virome
The gut microbiome is a critical part of human health. Research has shown that many types of bacteria may reside there. ...
NOV 05, 2021
Genetics & Genomics
Solution to a Pigeon Genetic Mystery Provides Insight Into Development
NOV 05, 2021
Solution to a Pigeon Genetic Mystery Provides Insight Into Development
This photo by Sydney Stringham shows the domestic pigeons that were bred by the researchers for this research.
NOV 08, 2021
Genetics & Genomics
Revealing Gene Expression Networks in Human Embryonic Stem Cells
NOV 08, 2021
Revealing Gene Expression Networks in Human Embryonic Stem Cells
Advances in genetic and computational tools have enabled researchers to study complex networks of gene expression in ind ...
NOV 14, 2021
Microbiology
Beneficial Bacteria May Help Fight Ear Infections Caused by Bacterial Pathogens
NOV 14, 2021
Beneficial Bacteria May Help Fight Ear Infections Caused by Bacterial Pathogens
Researchers have identified bacteria that have the potential to fight infections that affect the middle ear and can caus ...
Loading Comments...