ACHOO!

Photic Sneeze Reflex

Does this scenario sound familiar? You leave a movie theater, or a dimly-lit brunch spot, and step into sunshine. Suddenly your nose gets tickly— ah-ah-ah-choo! If you've always suspected sunlight makes you sneeze, you may have a genetic trait called the photic sneeze reflex.

How it works

Exposure to bright sunlight causes some people to sneeze. Scientists are still trying to understand this reflex. In the meantime, they've come up with a couple of theories, as well as a clever name: "Autosomal Dominant Compelling Helio-Ophthalmic Outburst," or "ACHOO Syndrome."

The genetic link

Scientists originally thought this reflex was probably due to a single genetic variant based on the way the trait is passed down through families. However, it looks like a lot of genetic factors may be responsible for ACHOO syndrome. 23andMe researchers have identified at least 54 genetic markers so far.

Sun sneezing

Did you know?

You really should cover your sneezes, even ones caused by bright sunlight. Each sneeze sprays thousands of tiny droplets surprisingly far and fast: they can go farther than two and a half feet, and move at speeds of up to 12 mph. Gesundheit!

Explore more

Think you have ACHOO Syndrome? 23andMe's Health + Ancestry Service is nothing to sneeze at. Just pick up the kit, spit, and we'll help shine some light on whether you're likely to have the photic sneeze reflex based on your genetics.

Health + Ancestry Service Kit

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