Following the outbreak of the CCP virus outbreak, a phenomenon has been noticed that some people are more susceptible to the virus than others, some infected people are more likely to develop symptoms than others, and the severity of symptoms varies significantly from patient to patient. However, to date, scientists still know what is going on and are still searching for the underlying causes behind the phenomenon.
Genes are an entry point for research in this area. Which segments on the deoxyribonucleic acid (DNA) are associated with CCP pneumonia? If such an association can be found, does it mean that the strength of resistance to CCP pneumonia in each individual is actually determined by genetic predisposition?
Comparing the entire genome on the DNA sequence one by one, scientists hope to determine if there is an association between specific genetic changes and specific diseases.
So far, two clues have been identified that are worth pursuing: changes in two segments of DNA located on chromosome 9 and chromosome 3, respectively.
Vikki Rand, professor of biology at Teesside University, and Maria O’Hanlon, a PhD student in biology, wrote about these two intriguing lines of research on The Conversation, a scholarly website.
SCIENCE PHOTO LIBRARY Genes that can be traced back to Neanderthal caveman DNA may be a risk factor
- Genetic risk
The clues on chromosome 3 are relatively simple. Studies of Spanish and Italian patients have found that severe disease caused by the virus is associated with changes in a small region on chromosome 3; this small segment of chromosome is numbered 3p21.31.
This region contains a gene, SLC6A20, that carries the genetic information for instructions to make a protein that interacts with a molecule called ACE2 that the virus uses to enter the cell.
Other genes on this chromosome carry genetic information that targets the chemokine receptor, a receptor associated with inflammation.
Since both ACE2 and inflammation are central factors in COVID-19 severe disease, they may provide clues to explain why variants in this region of chromosome 3 are associated with severe disease.
This chromosomal variation that leads to increased susceptibility to CCA virus may have been inherited from the ancient ancestor Neanderthal caveman.
To date, 3p21.31 is the only segment of the genetic region that has been significantly associated with Neocon severe disease. Therefore, genetic variants in this region can be considered as risk factors.
Image source, REUTERS
- Blood type and CCA virus
The segment on chromosome 9 is the ABO blood group system, which determines the blood type of each individual.
This clue points to an association between blood type and susceptibility, i.e., are people with a certain blood type relatively less susceptible to viral infections and less likely to become seriously ill or die from the disease after infection? If the answer is yes, then isn’t the key to further validating this association that antibodies in the blood can prevent the virus from invading cells?
Some studies early in the European Epidemic found a possible association between blood types O and AB and new crowns, while others concluded that blood type had no effect on the consequences of viral infection.
As the outbreak spread, the number of infections increased, and the size of the studies expanded, a pattern emerged: people with blood type A were more likely to develop the disease than those with blood type O, who were less likely than other blood types to develop serious illness after contracting the virus.
But these studies were not credible enough because of the small sample size, and at best provided a possible direction.
A later study of cases of respiratory failure associated with the CCA virus found that patients with blood type O were less likely to develop respiratory failure than patients with other blood types, while patients with blood type A were 1.5 times more likely to develop respiratory failure than patients with other blood types. The sample for this study included 1600 patients from Spain and Italy.
The study was then supported by a published paper.
This paper analyzed and evaluated seven unrelated studies with a total sample of nearly 3 million people, including 7,500 patients with Neocon. The results of the evaluation found that the groups that tested positive for the CCP virus were predominantly A-group, while the O-group was less likely to be infected with the CCP virus.
This result was subsequently supported by a much larger study in Canada; the latter study found that people with blood type O had about a 12 percent lower risk of infection and a 13 percent lower risk of serious illness or death than people with other blood types.
So, the question is whether there is any association between blood type and susceptibility to the CCP virus?
According to studies conducted after the 2002-2004 Sars (SARS) outbreak, the lower probability of contracting the CCP virus in people with O blood type was a possibility that was raised, and one explanation at the Time was that antibodies in O blood type might be able to prevent the Sars virus from invading cells.
However, this hypothesis has not yet been tested.
What is certain now is that Covid-19, like Sars, is a coronavirus.
Scientists hope that more samples, more data and more research will lead to more clues and discover a clearer lineage.
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