Autosomal-dominant Compelling Helio-Ophthalmic Outburst syndrome….. ACHOO!!!!!

For 10-35% of the population, looking at a bright light will cause them to reflexively sneeze. This genetic anomaly is called the photic sneeze reflex. The reflex is autosomal dominant. Though it has yet to be fully understood scientifically, it is hypothesized to be caused by the close proximity of the trigeminal and optical nerves to one another. The trigeminal nerve is the cranial nerve that controls facial sensation and motor control. When bright light enters the eye, the optic nerve sends a signal to the brain to constrict the pupils. The theory is that the electrical impulse sent through the neurons is sensed by the trigeminal nerve and is mistaken as an irritant to the nose, causing the body to sneeze.

Identifying what gene is responsible for the photic sneeze reflex could be critical in the research of other light-sensitive phenomena in humans. Epileptic seizures and migraines can be caused by light stimuli. Louis Ptacek, a leading neurologist, believes that discovering the gene that causes photic sneezing could lead to greater knowledge of the visual pathway and potentially how light affects people with other light sensitive conditions.

This is a summary of an article from Scientific American: "Looking at the Sun Can Trigger a Sneeze."