An
autosomal recessive genetic disorder common among
white folk. The
gene was
discovered to rest on
chromasome 7 in 1989.
Cystic Fibrosis affects the exocrine glands, which are in charge of secreting sweat and mucus. In sufferers, the glands produce a thick, sticky mucus. The gene also codes for a flawed protein that affects movement of the chloride ion through the walls of the lungs and the gut. This means that a layer of sticky, concentrated snot accumulates in the lungs, which impairs breating and aggravates respiratory infections.
In the stomach, the mucus interferes with digestive enzymes, blocking normal absorption of nutrients. This means that a person with CF can become malnourished, even with a proper diet. britannica.com says that greasy, foul-smelling stools are the first warning sign of CF, although I'd think that they'd also just indicate too many chili dogs, so don't jump to conclusions.
The definitive test for CF is the sweat test, in which a subject's sweat is measured for abnormally high salt content, another symptom of CF.
Treatment for CF means taking enzyme supplements, and a diet high in calories, protein, and fat. Sounds like the lush life, but you've also got to get some strenuous exercise in your day so you can loosen up those mountains of snot in your lungs. Antibiotics are also needed to fight respiratory infection. If you suffer from CF and you follow these steps, you have a good chance of surviving it past childhood.
Major props to britannica.com for providing almost all the hard data in this writeup. Thanks also to alex.tan for the autosomal and chlorine channel info.