Why do some people with coronavirus have only mild symptoms while others have fatal conditions? Geneticists have been roaming our DNA for clues.
Now, European scientists have concluded from a study of the first of its kind, which documents a strong statistical link between genetic differences and Covid-19. The researchers discovered that the differences are concentrated in two points in the human genome related to an increased risk of respiratory failure in Covid-19 patients. One of these points contains the gene that determines the blood type.
If the patient's blood group is, according to the new study, “A”, there is a 50% chance that he needs oxygen or a ventilator. The study also revealed amazing information about the genes that failed to appear.
Coronary virus is bound to a protein called ACE2 that appears on the surface of human cells in preparation for entry. However, the genetic variants of ACE2 do not appear to make any difference in the risk of acute infection with Covid-19.
The results indicate that relatively undiscovered factors may play a major role in the development of life-threatening Covid-19 cases. "There are new children about to emerge now," says André Franky, co-author of the molecular genetics at the University of Kiel, Germany.
Scientists have already determined that factors such as age and underlying disease put people at additional risk of developing an acute condition of Covid-19. However, genetics hope that the DNA test will help in identifying patients who will need intensive treatment.
As the epidemic gained momentum in February, Dr. Frankie and his colleagues collaborated with doctors in Spain and Italy who were suffering from an escalating wave of Covid-19.
Doctors took blood samples from 1610 patients who needed oxygen supplies or had to use a ventilator.
Dr. Franky and his colleagues extracted and scanned DNA from samples using a rapid technique called genotyping.
The researchers did not track the sequence of all three billion genomes in each patient. Instead, they looked at nine million characters. The researchers then conducted the same genetic survey of 2,205 blood donors without finding any evidence of Covid-19.
Scientists were looking for spots in the genome, called loci, where an unusually large number of severely ill patients share the same variables with the rest of the patients, compared to those who did not have the disease.
Two spots appeared. In one of these spots is the gene that determines our blood group. This gene directs the production of protein that puts molecules on the surface of blood cells.
This is not the first time that blood has shifted from the "A" group to a potential risk. Chinese scientists who have examined the blood group of patients also found that people with "A" group were more likely to have serious Covid-19 infection.