Do you sneeze at the Sun? You may have a genetic condition known as Achoo Syndrome. Really.
Sneezing when you look at the Sun, or sometimes any bright light, is called a photic sneeze reflex. The reflex is known as Achoo Syndrome, an anagram of “autosomal dominant compelling helio-ophthalmic outburst.” It is triggered by a change in light intensity – seeing bright light after seeing dark such as walking out of a dark theater or driving out of a dark tunnel.
Aristotle noticed the photic sneeze reflex, but it was first officially identified by a physician who noticed that some patients sneezed when he used an ophthalmoscope which casts light into the eye to examine the retina.
Scientists are not sure why the change in light intensity causes the sneeze reflex. Some theories include the light stimulating the optic nerve or causes the production of tears which might irritate the nose.
The sneeze produced in the 18-35% of people with this syndrome is different from a sneeze caused by an irritant such as dust. Photic sneezes are usually multiple sneezes – as few as two or three but sometimes many more.
Achoo Syndrome is autosomal which means that the gene for the trait is carried on the first 22 pairs of chromosomes and not on the sex chromosomes. Pair 23 are the sex chromosomes – XX for females and XY for males. The gene for photic sneezing is (coincidentally?) located near a gene that causes light induced seizures.
Achoo Syndrome is also dominant. This means that a person only needs to inherit the gene from one parent to exhibit the reflex. If you have Achoo Syndrome, it’s likely that someone else in your family does also.
Most of the people who have Achoo Syndrome are female and white.
For more information, visit these Healthline or BBC articles.
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