For many patients, a loss of taste or smell is one of the first signs that they have COVID-19. Researchers have now identified certain genetic variations in patients that may increase the risk of the coronavirus robbing them of their senses.
Researchers found that persons with certain genetic alterations on chromosome 4 were 11 percent more likely to lose their ability to smell or taste than people without the mutations, according to a study published in Nature Genetics on January 17th. People who had their DNA examined by the genetic testing company 23andMe and self-reported a case of COVID-19 provided the data.
Two genes that help individuals smell, UGT2A1 and UGT2A2, are discovered in a region of chromosome 4 linked to sensory loss after infection, according to epidemiologist Janie Shelton of 23andMe and colleagues. Both genes create enzymes that metabolize odorants, compounds that produce unique odors.
According to studies, infections in scent-supporting cells termed sustentacular cells cause loss of smell, which is a defining sign of COVID-19 (SN: 6/12/20). According to Shelton, genetic variations near UGT2A1 and UGT2A2 may influence how the two genes are turned off, causing scent problems during an infection.
Because the researchers combined the loss of smell and taste in one survey question, the researchers were unable to determine if genetic polymorphisms play a role in losing one sense over the other. “When you lose your ability to smell, your taste is typically severely impaired,” Shelton explains. Taste can fade away without causing olfactory loss.
According to Shelton, even after the coronavirus has left their bodies, some patients lose their sense of smell. Researchers may be able to resurrect sniffing capabilities to figure out how the virus disables it.
