What is cystic fibrosis (CF)?

Cystic fibrosis (CF) is a genetic (inherited) disease that causes sticky, thick mucus to build up in organs, including the lungs and the pancreas.

In a healthy person, mucus that lines organs and body cavities, such as the lungs and the nose, is slippery and watery. In people who have CF, thick mucus clogs the airways and makes it difficult to breathe. Blocking the ducts in the pancreas causes problems with digesting food, so babies and children who have CF may not be able to absorb enough nutrients from food.

Other organs that are affected by CF are the liver, sinuses, intestines and sex organs. CF is a chronic (long-lasting) and progressive (getting worse over time) condition.

How common is cystic fibrosis (CF)?

Among white children in the United States, the rate of CF cases is one in 3,500 newborns. CF affects about one in 17,000 black newborns and one in 31,000 newborns of Asian descent.

What causes cystic fibrosis (CF)?

CF is passed through the CFTR genes. People who have CF inherit two faulty genes, one from each parent. The parents do not have to have CF; in fact, many families do not have a family history of CF. In this case, the person with the faulty gene is called the carrier. About one in 31 people in the United States is a carrier who is free of CF symptoms.

What are the symptoms of cystic fibrosis (CF)?

Children who have CF have the following symptoms:

  • Failure to thrive (inability to gain weight despite having a good appetite and taking in enough calories)
  • Loose or oily stools
  • Trouble breathing
  • Recurrent wheezing
  • Frequent lung infections (recurrent pneumonia or bronchitis)
  • Recurrent sinus infections
  • A nagging cough
  • Slow growth

Last reviewed by a Cleveland Clinic medical professional on 06/13/2019.


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