A Faulty Gene Increases Risk of COVID-19 in Dementia Patients

Out of nowhere, the outbreak of COVID-19 is becoming night terrors for the patients of dementia as the disease becomes the second most comorbid with COVID-19 after diabetes mellitus (DM), according to the data from England compiled by the National Health Service (NHS).

However, researchers from two academic institutions including the University of Exeter Medical School (UEMS) and the University of Connecticut School of Medicine (UCSM) have recently found that a faulty gene known as APOE e4e4 may play a key role in causing the deadly coronavirus. The study titled ‘APOE e4 genotype predicts severe COVID-19 in the UK Biobank community cohort’ has been published in the Journal of Gerontology, Series A.

Usually, patients of Alzheimer’s disease (AD) or any other dementia do not have any link with respiratory illnesses such as COVID-19 just like the new coronavirus does not associate with a high risk of forgetfulness like symptoms that mostly a part of neurodegenerative disorders.

One thing that might connect the AD or dementia patients with the novel coronavirus is either genetics or ‘forgetfulness’. The early precautions that should be done to not catch the deadly virus are hand washing or maintaining a social distance from others.

People with dementia may forget these precautions to take that can result in an early development COVID-19 that has sickened more than 5.8 million people with above 357,00 deaths, around the globe. An estimation of over 2,361,000 people has been recovered from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), according to data compiled by mixed resources including Johns Hopkins University (JHU) and worldometer.

Source: Reuters Graphics

The researchers analyzed European Americans. They collected data from the UK Biobank (UKB). It was comprised of a total of 382,188 participants. The team’s focus of attention was to observe the gene, APOE e4e4 that mainly known as to affect cholesterol levels in the body and those mechanisms involved in inflammation. It also plays a role in increasing the risk of heart disease and dementia.

Following results from the analysis, the team determined that more than 9,000 participants carried two copies of the APOE e4e4 faulty gene that have the potential to increase 12 times greater risk of developing AD whereas, more than 223,000 had two copies of APOE e3e3.

After the team got the numbers of the people who got the faulty gene, the attention switched to the number of COVID-19 patients, so they cross-referenced the previous numbers with people who tested positive for COVID-19 between March 16 and April 26.

The results reveal, while 401 had two copies of the e3 variant. After taking into account various factors, including age and sex, the team say people with two e4 variants had more than double the risk of severe Covid-19 than those with two e3 variants

Through the comparison between a4 and a3 gene and other factors including age and gender, the investigators found out that 37 and 401 participants who tested positive for Covid-19 had two copies of the e4 and e3 variant of ApoE, respectively. They also determined that a4 homozygous genotype was associated with a doubled risk of severe Covid-19 as compare to those people who had two copies of e3.

Health Units reached out to David Melzer, study’s co-author, and Professor of Epidemiology and Public Health, University of Exeter Medical School, and Professor, University of Connecticut Center on Aging, and asked him how APOE e4e4 genotype is more fatal in patients with no preexisting Alzheimer’s or dementia. He says:

ApoE has been implicated in influencing the severity of several virus infections including HIV. There are several theories on how it might be working, but no firm data on this new coronavirus. We hope our research will stimulate laboratory and clinical studies to clarify the biology underlying the risk.

When asked how their research findings will help in developing better treatments for Covid-19, he said:

We hope other studies will now test this association and laboratory studies will follow to understand how the gene is altering risk. Discovering the mechanism could lead to new ideas about treatment targets.

David Melzer also 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. The effect could be partly due to this underlying genetic change, which puts them at risk for both COVID-19 and dementia.”

There is a need for more research on the association between COVID-19 and dementia because it is not enough to say that the ApoE e4 allele (gene variant) can be a single risk factor for severe Covid-19 infection.

Care inspectorate has introduced special care services during the COVID-19 outbreak for the patients that are suffering from dementia that can be referred to as those conditions in which a person experiences a progressive decline in memory, language, problem-solving, and other thinking skills due to damage to the brain cells.

The World Health Organization (WHO) has reported that nearly 50 million people have been diagnosed with dementia with almost 10 million new cases annually.

Source: Dementia Parternership- World Alzheimer Report 2015

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