Commonly affected are the lungs, pancreas, and sweat glands. Mucus in the lungs can block the bronchi, making breathing difficult.
Thick mucus can also block the ducts of the liver and the pancreas, causing improper digestion.
In most cases, persons with cystic fibrosis seem to be born healthy, but begin showing signs of this disorder between infancy and adolescence. It seems that the sweat glands are also affected by this disorder. They produce excessive amounts of salt, which can be detected by testing perspiration samples. The abnormal gene that gives rise to cystic fibrosis has been found and can now be reliably tested for. There is no known cure for this disorder, but treatment with many new antibiotics is allowing children with cystic fibrosis to reach adulthood.