Cystic fibrosis is a condition that causes the body to produce thick, sticky mucus. This inherited disease most often causes health problems that affect the lungs, pancreas, liver, reproductive organs and sinuses. About 30,000 Americans and 70,000 people worldwide have cystic fibrosis, according to the Cystic Fibrosis Foundation. It is the most common serious genetic disease in white Americans.

In a healthy person, mucus is watery and helps keep the linings of organs moist. This prevents them from drying out and becoming infected. Mucus also helps protect the openings to the body. In cystic fibrosis, a genetic abnormality causes the body to produce thick, sticky mucus that is characteristic of the disease.

As the mucus builds up in the lungs, it blocks the airways and creates an environment in which bacteria can grow. As a result, patients experience chronic lung infections that cause cumulative (increasing over time) damage to the lungs. The infections in people with cystic fibrosis are most frequently caused by the bacterium Pseudomonas aeruginosa, which rarely causes infections in people without the disease.

The mucus also may block ducts in the pancreas, which prevents the digestive enzymes made by the pancreas from reaching the small intestine. Without these enzymes, the body cannot fully absorb fats and proteins. This can lead to malnourishment, bulky stool, a lack of certain vitamins (A, D, E and K), and other symptoms such as intestinal gas, a swollen abdomen, and pain or discomfort.

The abnormal gene that triggers cystic fibrosis also causes sweat to become very salty. During heavy perspiration, the body may experience a mineral imbalance that may require emergency treatment.

Respiratory failure is the chief cause of death in patients with this illness. However, medical advances have increased the average life span of a person with cystic fibrosis to more than 35 years, according to the National Institutes of Health.