What is Cystic Fibrosis?

Every year, 1000 children with Cystic Fibrosis are born in the United States. A person must inherit two defective genes-one from each parent-to develop this disease. CF usually begins in infancy.

CF affects tissues that produce mucus secretions, such as the airway, the gastrointestinal tract, the ducts of the pancreas, the bile ducts of the liver. In the lung, mucus also transports dust and other particles out of the airway and helps to prevent infection. The most characteristic symptom of CF is the excessive production of thick mucus in the airways. CF alters the mucus and the abnormal mucus obstructs the ducts of the airways, causing tissue damage. CF patients cough frequently and require time-consuming daily chest and back clapping and body positioning to drain lung secretions. Because the mucus provides an ideal breeding ground, CF patients have frequent airway infections. Among the most common germs in CF patients are Pseudomonas bacteria. This germ is diffucult to clear in CF patients, even after antibiotics. Typically, CF patients have a pattern of low-grade, persistent infection with periodic worsening, requiring hospitalization. Recurring Pseudomonas infection and the inflammation that accompanies it damages the lungs, causing respiratory failure, which is the leading cause of death among CF patients.

As in the lungs, thick mucus clogs the pancreatic ducts and damages the pancreas. The pancreas supplies digestive enzymes. Most CF patients have insufficient amounts of digestive enzymes for normal digestion. Pancreatic insufficiency causes foul-smelling, bulky bowel movements, malnutrition and slowed growth and development. Replacement of pancreatic enzymes can alleviate these symptoms. As the disease progresses, the cells in the pancreas become damaged and patients may develop diabetes.

Salt absorption in the sweat ducts is also impaired, and CF patients produce extremely salty sweat. Based on this observation, a sweat test to diagnose CF was developed.

The symptoms and severity of CF vary from patient to patient. Not all patients suffer from impaired pancreatic function. The degree of lung disease also varies.

Improvements in antibiotic therapy, clearance of lung secretions, nutritional support, and the collection of patients at centers for expert care have increased the mean survival of patients with CF from under 5 years to approximately 30 years. But despite this progress, there still is no cure for the disease and until this is achieved, the pulmonary infection and inflammation that ultimately leads to respiratory failure and premature death remains prime targets for therapy. Since the 1989 identification of the gene which is altered in CF, scientists hope to improve the lives of patients with this genetic disease and find a cure for this disease.