Mayo Clinic: DNA may determine the severity of each individual COVID-19 case

Mayo Clinic researchers say they may have found a genetic explanation for why COVID-19 is severe in some people and mild in others.

If the research holds, knowledge of how the SARS-CoV-2 virus behaves would be a stark contrast from the beginning of the pandemic, when all groups deemed potentially vulnerable took extra caution for fear of infection.

According to Mayo Clinic, the Rochester scientists have discovered mutations in two human proteins that might determine how susceptible an individual is to COVID-19 symptoms.

Researchers examined DNA sequence data from around the world to look for differences that could affect “disease outcome.” The findings are linked to the key idea that proteins play many critical roles in the function of the human body.

“To our knowledge, it’s the first time anyone has applied this approach to COVID-19,” said study co-author Dr. Richard Weinshilboum.

Many people may be uncertain what human proteins are and what they do in the human body.

The National Institutes of Health (NIH) information says proteins, which are large and complex molecules in our bodies, do most of the work in our cells and are necessary for the function of bodily tissues and organs.

Our DNA contains the instructions to make those proteins. Therefore, genetic differences from person to person influence proteins.

In order to demonstrate the importance of protein expression to disease in general, the NIH National Cancer Institute says protein expression in cancer cells may be linked to specific types of cancers and how effective certain treatments will be. The cancer institute defines protein expression as “the production of proteins by cells.”

While the COVID-19 virus and cancer are very different, the release of the Mayo Clinic study highlights one way scientists are attempting to uncover how COVID-19 has led to millions of deaths worldwide while other infected people never experience a single symptom.

“Variants in the genes for ACE2 and TMPRESS2 can lead to an increase or decrease in protein expression. An increase in protein expression might result in elevated COVID-19 susceptibility and severity, while a decrease might have a protective effect against the virus… In this case, ACE2 and TMPRESS2 provide critical entry points for SARS-CoV-2 to invade and infect human cells,” the Mayo Clinic release explained.

The study was done by a Mayo Clinic team in Rochester, and was led by Lingxin Zhang from the Mayo Clinic Division of Clinical Pharmacology.

A PDF version of “ACE2 and TMPRSS2 SARS-CoV-2 infectivity genes: deep mutational scanning and characterization of missense variants,” published in Human Molecular Genetics, can be found here.