COVID-19: People with blood group A may be at higher risk. This is not the only genetic condition
Why do some people struggle with COVID-19 having tougher symptoms while others seem to be resistant to coronavirus? The answer may be in the genes – say scientists analyzing the DNA of seriously ill people. They found two places that appear to be associated with a higher risk of developing severe respiratory failure.
People with blood group A may be more at risk of having severe COVID-19 condition
Geneticists from the Christian-Albrecht University of Kiel (Germany) came to this conclusion. This is one of the first studies showing a strong statistical relationship between some genes and susceptibility to serious complications of COVID-19. These are certain genes located in two places (called loci) of our genome. One of them is associated with a gene that is responsible for the blood group.
“People with blood type A have a 50 per cent chance that they will have very hard COVID-19 condition and will require breathing support,” the researchers stated. On the other hand, genetic variants associated with the ACE2 receptor, that is, to which the coronavirus “sticks” do not seem to matter here – the researchers note. They do not increase the risk of developing severe COVID-19.
If the discoveries were confirmed, this would mean that, for example, a genetic test could be developed that detects gene variants that increase the risk of severe respiratory complications in infected people. This would be helpful for doctors planning treatment because they could determine quite early which patient may require intensive treatment.
In addition, finding the answer to the question of why certain gene variants are conducive to severe complications of COVID-19 may give specific guidance to scientists working on new drugs or therapies.
Geneticists have been conducting research since the outbreak of the epidemic
German geneticists began their research at the very beginning of the epidemic when the coronavirus appeared in northern Italy and Spain. They then took blood samples from 1610 patients from intensive care units who had to be given oxygen or be attached to a respirator. Then, DNA fragments were extracted from their blood and scanned. To this end, a technique called genotyping is used. It is the process of looking for differences in genetic patterns or genotypes by examining DNA sequences and then comparing, e.g. with a reference DNA sequence. In this case, DNA samples from 2205 uninfected individuals were taken for comparison.
Researchers were looking for places (loci) where the same genetic variants appear in COVID-19 patients and this was linked to the severe course of the disease, and then compared with analogous places in the genotype of healthy people. Two loci were found that puzzled geneticists.
One of these places is the gene that codes for proteins located on the surface of blood cells. It determines what type of blood we have. For COVID-19, it is riskier to have group A, the researchers said.
There are earlier studies carried out in China that suggest COVID-19 may have something to do with blood groups. Researchers have noted that patients with blood group A seem to have a higher risk of severe COVID-19. Now their conclusions coincide with analyzes of German geneticists.
Unfortunately, it is not known why this happens. Dr Andre Franke, co-author of the research notes that in the area where the blood group gene is located, there is also a DNA fragment responsible for turning on and off the gene that manages the production of the protein that triggers the body’s strong immune response, the so-called cytokine storm. Cytokine storm is a major cause in COVID-19 complications. But that is just a hypothesis for now.
Six “suspicious” genes
Elsewhere in the DNA (on chromosome 3), six genes were found that stood out in people who were seriously ill with COVID-19. But for now, it is not known which of them are linked to the disease. These are the genes responsible for coding the protein that interacts with the ACE2 receptor, as well as genes that code for immune proteins.
These are probably not all the genes that have something to do with COVID-19 and we may be faced with many discoveries. Geneticists in many countries are now working intensively as part of the COVID-19 Host Genetics Initiative project, which brings together more than 1,000 scientists from 46 countries.
Sources : medRxiv.org , New York Times , COVID-19 Host Genetics Initiative