Spanish and Dutch scientists have identified two new mutations in the TLR7 gene in healthy young men who fell ill with a severe form of COVID-19. As the researchers write in an article published in the journal Frontiers in Immunology, mutations can undermine the immune defense, making a person more susceptible to the coronavirus.
It is already known that mutations in the TLR7 gene can be a rare genetic risk factor for severe COVID-19. Earlier, researchers reported that two unrelated pairs of brothers became seriously ill with the coronavirus, and one of them died. All of them had a mutation in the TLR7 gene, which encodes a receptor important for the recognition of coronavirus and initiates an antiviral immune response through the induction of interferons. Thus, this gene serves as an important factor of protection against SARS-CoV-2.
An Italian study involving men over 60 with a severe form of COVID-19 showed that more than two percent of seriously ill patients carry a genetic mutation in TLR7. This leads to a violation of the functioning of the corresponding receptor. Scientists observed a difficult activation of the transmission of interferon signals, resulting in which the optimal immune response could not develop.
In a new study, experts analyzed 14 cases of severe COVID-19 in young men under the age of 50. So far, unknown mutations of the TLR7 gene were detected. In one patient, a resident of the Netherlands, a defective activation of signal transmission and a violation of interferon production was again observed. At the same time, two cousins of the Dutch patient, who have not yet been exposed to the coronavirus, showed the same mutation. To reduce the risk of serious illness, they underwent preventive vaccination.