23andMe team targets loci associated with loss of smell and taste in COVID-19 patients

Decreased sense of smell and taste is one of the main symptoms of COVID-19, but the underlying biological mechanism is still unclear

The paper, titled "The UGT2A1/UGT2A2 locus is associated with COVID-19-related loss of smell or taste," was published in the journal Nature Genetics

"As far as we know, this is the first time a genetic link to this symptom has been found, and it will hopefully help us understand how the virus interacts with our bodies," said Adam Auton, senior author of the paper and vice president of human genetics at 23andMe

The study cohort included nearly 70,000 people who tested positive for SARS-CoV-2 at some point, 68% of whom said they experienced a loss of smell or taste, compared with 32% who did not

Following a multi-lineage meta-analysis, the researchers conducted separate association studies in five representative lineage groups

The researchers then performed phenotypic association studies on the indexed SNPs using the 1,300 phenotypes in the 23andMe database

There are four genes within this 150 kb indexed SNP, namely UGT2A1, UGT2A2, UGT2B4 and SULT1B1

The researchers believe that these results suggest that UGT2A1 or UGT2A2 may play a role in the loss of smell or taste in COVID-19 patients, but the exact mechanism remains unclear

Auton added that multiple factors can affect the loss of smell or taste, including how sensitive the patient was before the infection and the severity of the infection

However, the researchers noted that the study also had limitations because it relied on self-reports and could not distinguish between smell or taste

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Shelton, JF, Shastri, AJ, Fletez-Brant, K.