Photic Sneeze Reflex & Genetics

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.

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.

References

Bhutta MF. (2015). “Sneezing Induced by Bladder Fullness.” Int J Urol. 22(2):239.

Dean L et al. (2012). “ACHOO Syndrome”.

Duguid JP. (1946). “The size and the duration of air-carriage of respiratory droplets and droplet-nuclei.” J Hyg (Lond). 44(6):471-9.

Eriksson N et al. (2010). “Web-based, participant-driven studies yield novel genetic associations for common traits.” PLoS Genet. 6(6):e1000993.

Forrester JM. (1985). “Sneezing on exposure to bright light as an inherited response.” Hum Hered. 35(2):113-4.

Langer N et al. (2010). “When the sun prickles your nose: an EEG study identifying neural bases of photic sneezing.” PLoS One. 5(2):e9208.

Nishimura H et al. (2013). “A new methodology for studying dynamics of aerosol particles in sneeze and cough using a digital high-vision, high-speed video system and vector analyses.” PLoS One. 8(11):e80244.

Songu M et al. (2009). “Sneeze reflex: facts and fiction.” Ther Adv Respir Dis. 3(3):131-41.

Teebi AS et al. (1989). “Autosomal Dominant Sneezing Disorder Provoked by Fullness of Stomach.” J Med Genet. 26 (8):539–40.