There is a disorder called "Ondine's Curse" that causes people to lose the ability to breathe involuntarily.
Obviously, we all breathe without forcing ourselves to. The first thing one might think, then, is how can one with Ondine's Curse even fall asleep without dying? Surprisingly, 1 in 200,000 children are born with this disorder, named after the myth of Ondine. The story goes that Ondine was a water nymph who cursed her unfaithful lover to only be able to breathe while he was awake. Also called Primary alveolar hypoventilation, it most often occurs at birth, but can happen due to trauma to the brain stem as well. There is no known cure, but among the best solutions, one is a tracheotomy (cutting a hole in the throat through the voice box) to place a tube that allows breathing without use of the nose or mouth. The other is attaching a sort of breathing apparatus to the upper body called in a method called “Biphasic cuirass ventilation.”
Unfortunately, this disorder is rarely survived. Other effects of Ondine's Curse include darkening of skin color, drowsiness, fatigue, headaches, high blood pressure, and insomnia. Those who suffer from Ondine's Curse often also are more sensitive to sedatives and narcotics.
Despite the rare survivability rate to this disorder, to the right is one boy who's lived his entire life with it. He proves it can be lived with!