A
genetic variant that raises one’s risk of developing Alzheimer’s disease may
also make people more susceptible to COVID-19. 

People
with two copies of a version of the APOE gene called APOE4 are 14 times as likely to
develop Alzheimer’s disease as people with two copies of the APOE3 version of the gene (SN: 9/22/17). Those people were also
more than twice as likely to test positive for the
coronavirus than people with two copies of the APOE3 version, researchers report May 26 in the Journals of
Gerontology: Series A
. The results come from a study of more than 600
people in England diagnosed with COVID-19 from March 16 to April 26.

Two
previous studies showed that people with dementia were more likely to have
severe cases or to die of COVID-19. This new study found that even people with
no signs of dementia or other diseases associated with having APOE4 were still more susceptible to
COVID-19 than people with the APOE3
version. 

Among
nearly 400,000 participants in the large genetic database called the UK
Biobank
,
only 3 percent have two copies of APOE4,
while 69 percent have two copies of APOE3.
The remainder have one of each version. 

But
the APOE4 version was more common
than expected among people diagnosed with COVID-19, the study found. Of 622
people who tested positive for the coronavirus, 37 had two copies of APOE4. On a population scale, that means
about 410 of every 100,000 people with two copies of that version of the gene
would test positive, the researchers calculate. That compares with 179 of every
100,000 people with two copies of APOE3
testing positive.

APOE is involved in handling cholesterol in the body and the protein also plays a role in some immune system functions. Exactly how APOE4 may make people more vulnerable to the coronavirus isn’t understood yet.