What is cystic fibrosis?




What is cystic fibrosis?

In people with CF, a defective gene (mutation) causes a thick, buildup of mucus in the lungs, pancreas and other organs. In the lungs, the mucus clogs the airways and traps bacteria leading to infections, extensive lung damage and eventually, respiratory failure. In the pancreas the mucus prevents the release of digestive enzymes that allow the body to break down food and absorb vital nutrients, produce insulin, and secrete bicarbonate.

Did you know?

Symptoms of CF

People with CF can have a variety of symptoms, including:

    • Very salty-tasting skin
    • Persistent coughing, at times with phlegm
    • Frequent lung infections including pneumonia or bronchitis
    • Wheezing or shortness of breath
    • Poor growth or weight gain in spite of a good appetite
    • Frequent greasy, bulky stools or difficulty with bowel movements
    • Male infertility

In the United States

  • About 40,000 people are living with cystic fibrosis (70,000 worldwide).
  • Approximately 1,000 new cases of CF are diagnosed each year.
  • More than 75% of people with CF are diagnosed by age 2.
  • Almost half of the CF population is over 18.

Diagnosis and Genetics

Cystic fibrosis is a genetic disease. People with CF have inherited two copies of the defective CF gene — one copy from each parent. Both parents must have at least one copy of the defective gene in order to have a child that expresses CF as a dominant gene.  People with only one copy of the recessive mutated CF gene are called carriers, but they do not have the disease (approximately 1 in 23 of the general population . . . that is 12 million people!). Each time two CF carriers have a child, the chances are:

  • 25% (1 in 4) the child will have CF
  • 50% (1 in 2) the child will be a carrier but will not have CF
  • 25% (1 in 4) the child will not be a carrier and will not have CF

The CF mutation contains a slight abnormality called a mutation. There are more than 1,800 known mutations of the disease. Most genetic tests only screen for the most common CF mutations.


Each day, people with CF complete a combination of the following therapies:

  • Airway clearance to help loosen and get rid of the thick mucus that can build up in the lungs. Some airway clearance techniques require help from family members, friends or respiratory therapists. Many people with CF use an inflatable compressive vest that vibrates the chest at a high frequency to help loosen and thin mucus.
  • Inhaled medicines to open the airways or thin the mucus. These are liquid medicines that are made into a mist or aerosol and then inhaled through a nebulizer. These medicines include antibiotics to fight lung infections and therapies to help keep the airways clear.
  • Pancreatic enzyme supplement capsules to improve the absorption of vital nutrients. These supplements are taken with every meal and most snacks. People with CF also usually take multivitamins.
  • Short and/or long acting insulin to manage CF Related Diabetes (CFRD) which is a hybrid of Type I & II diabetes.
  • Cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies to correct the malfunctioning protein made by the CFTR gene. Because different mutations cause different defects in the protein, the medications that have been developed so far are effective only in people with specific mutations.

  • The CF Foundation supports research to discover and develop new CF treatments that may dramatically improve the everyday lives of CF patients.

Today, the CF Foundation is focused on developing lifesaving new therapies for larger numbers of people with CF and pursuing daring, new opportunities to one day develop a lifelong cure.