Genetic Risk Factor Found for COVID Smell and Taste Loss, New Study Says

·3 min read

From the beginning of the pandemic, one of the most common—and straight-up weirdest—symptoms of COVID-19 has been the virus's tendency to cause a loss of taste or smell. For many, it was their first clue they were infected. Scientists still aren't sure why this happens (and it's become less common with the Omicron variant)‚ but a new study suggests the answer may be written, at least partially, in your genes. Read on to find out more—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.

1

What are Smell and Taste Disorders?

female cook standing at the hob in her apron tasting her food in the saucepan with a grimace as she finds it distasteful and unpalatable
female cook standing at the hob in her apron tasting her food in the saucepan with a grimace as she finds it distasteful and unpalatable

Loss of smell (anosmia) and loss of taste (ageusia) are symptoms that were identified in COVID-19 patients at the early stage of infection. According to John Hopkins Medicine, "symptoms can range from the not being able to smell or taste at all to the reduced ability to smell or taste specific things that are sweet, sour, bitter or salty. In some cases, normally pleasant tastes or smells may become unpleasant."

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2

Study Identified Two Involved Genes

Woman technician with multipipette in genetic laboratory PCR research
Woman technician with multipipette in genetic laboratory PCR research

In the study, researchers at the genomics company 23andMe looked at nearly 70,000 residents of the US and UK who reported testing positive for COVID. Sixty-eight percent of them said they lost their senses of smell or taste during the illness.

The scientists compared the genetic information of people who lost their sense of smell and those who didn't. They identified an area on the genome between two genes—UGT2A1 and UGT2A2—that was associated with either losing or retaining those senses. Both genes are expressed within the tissues of the nose and are involved in smell and metabolizing scents. Having that genetic variant increased the risk of losing taste or smell by 11%.

The researchers aren't sure exactly how UGT2A1 and UGT2A2 are involved, but they may influence the makeup of those nasal cells and their ability to either withstand or be affected by the COVID virus.

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3

How Does COVID Cause Taste or Smell Loss?

Portrait of young woman smelling a fresh and sweet nectarine
Portrait of young woman smelling a fresh and sweet nectarine

The study also found:

  • Women were 11 percent more likely to lose their senses of taste or smell

  • 73 percent of people who lost taste or smell were between the ages of 26 and 35

  • People of Asian or East Asian ancestry were less likely to lose those senses

"It was this really beautiful example of science where, starting with a large body of activated research participants who have done this 23andMe test, we were able to very quickly gain some biological insights into this disease that would otherwise be very, very difficult to do," said Adam Auton, a vice president at 23andMe and lead author of the study.

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4

How Does COVID Cause Taste or Smell Loss?

Scientist working in the laboratory
Scientist working in the laboratory

"How we get from infection to smell loss remains unclear," Dr. Justin Turner, an associate professor of otolaryngology at Vanderbilt University, told NBC News.

"Early data suggests that supporting cells of the olfactory epithelium are the ones mostly being infected by the virus, and presumably this leads to the death of the neurons themselves," he said. "But we don't really, really know why and when that happens, and why it seems to preferentially happen in certain individuals."

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5

How to Stay Safe Out There

Doctor had just vaccinated a young female patient in the hospital.
Doctor had just vaccinated a young female patient in the hospital.

Follow the fundamentals and help end this pandemic, no matter where you live—get vaccinated ASAP; if you live in an area with low vaccination rates, wear an N95 face mask, don't travel, social distance, avoid large crowds, don't go indoors with people you're not sheltering with (especially in bars), practice good hand hygiene, and to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.