Apr 15, 2021 - Health + Traits

The Genetics of Allergies

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For many people, sniffling, sneezing, and rubbing itchy eyes is a rite of spring.

Pollen wafting through the air from budding trees, grasses, and flowers during spring triggers allergy attacks for millions of people worldwide. A recent study indicated that climate change might be making the situation even worse for some due to the lengthening of the pollen season in North America.

Susceptibility to allergies — not just from pollen but also to things such as insect bites, dander from dogs and cats, or mold — is in part genetic. One’s environment also plays an important role in developing allergies. One silver lining of the last year is that mask-wearing during the pandemic appears to help lessen allergy symptoms in some, according to recent research done in Israel.

Researching the Genetics

Allergic reactions themselves happen when a hypersensitive immune system mistakes a normally harmless substance for a harmful one. When the immune system detects these so-called allergens, it triggers an immune response meant to protect the body. Research indicates that about half of those living in the U.S. are sensitive to at least one common allergen. While most allergic reactions are mild, some contribute to asthma or eczema and can be very serious and even life-threatening.

23andMe scientists and our collaborators have identified many genetic variants associated with allergies over the years. We also published studies on the genetic pathways for allergic rhinitis, genetic associations between allergies, eczema, and asthma, and the age of onset. That work allows us to understand not just the underlying causes better, but also offers researchers potential new targets for treatments. 

Cats and Dogs

People with allergies to dogs or cats react to the proteins found in animals’ saliva, their skin cells (also called “dander”), or urine. Those allergens trigger a response of the body’s immune system leading to sneezing, runny nose, watery eyes, and itchy skin. In some cases, people with dog or cat allergies may experience asthma symptoms, such as difficulty breathing or wheezing. For people with dog or cat allergies, lifestyle modifications and other treatments, including medications, can help ease symptoms.

It is estimated that 10 percent-to-20 percent of people are allergic to dogs or cats worldwide.

For 23andMe customers who want to explore a little deeper into their genetic likelihood of having certain allergies, we offer 23andMe+, an annual membership with 10+ exclusive reports and features delivered to you throughout the year‡.

Those reports are powered by 23andMe research and include new Wellness reports on cat allergies and on dog allergies. Both use statistical modeling that utilizes thousands of genetic variants, as well as a customer’s ethnicity and sex to estimate the likelihood of developing a dog or cat allergy.

Pets and Pollen

For those with pet allergies, preventing reactions isn’t as simple as you’d think. It’s not just about avoiding dogs and cats because pet allergens can travel easily through the air. They can stick to clothing and other surfaces, quickly spreading from place to place. In the United States, about half of households own a cat or a dog. Yet, studies have shown that detectable levels of pet allergens can be found in almost all homes, even ones that don’t own pets. High levels of pet allergens have also been found in public places like schools, offices, buses, and trains. To prevent reactions, experts recommend washing hands and clothes frequently.

Allergies to cats and dogs and allergies to pollens are alike in some ways. They are very similar in how they make their way into the body, what symptoms they cause, and how you treat them, for instance.

Finding Out More

Find out more about 23andMe’s Health + Ancestry Service or 23andMe+ membership here.

10+ reports and features will be added annually from January to December.

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