Learn About Cystic Fibrosis | American Lung Association

Learn About Cystic Fibrosis

Cystic fibrosis is a genetic (inherited) condition that leads to recurrent sinus and pulmonary infections, as well as gastrointestinal problems.

Key Facts

  • Cystic fibrosis is genetic.
  • People with this condition either don’t make enough or make an abnormal version of a protein called cystic fibrosis transmembrane regulator (CFTR).
  • CFTR is present on the cell surface in many organs and regulates the movement of salt-sodium (Na) and chloride (Cl) ions, as well as water across the cell surface.

What Is Cystic Fibrosis?

Cystic fibrosis (CF) is a genetic disease, meaning it is passed on from parents to their children through their genes. Both parents must pass on the abnormal gene (be a carrier (i.e., they each have one abnormal gene) for a child to be at-risk of developing the disease. 

Cystic fibrosis affects a specific protein called cystic fibrosis trans-membrane regulator (CFTR) that controls the normal movement of sodium (Na), chloride (Cl), as well as water in and out of the cells in different parts of the body. People with CF either have too little or abnormal CFTR.

When CFTR is absent or defective, the mucus normally secreted by the cells in the pulmonary airways (breathing tubes), pancreatic ducts, gastrointestinal tract, and reproductive system becomes thickened. This thickened mucus causes blockages (obstructions), frequent infection, and loss of function in the affected organs.

How Cystic Fibrosis Affects Your Body

Cystic fibrosis can affect the whole body.

  • In the lungs, malfunction of CFTR leads to thick mucus that obstructs the airways. When mucus is not cleared, it creates an environment for bacteria to grow and infect the airways. This leads to a vicious cycle with more mucus, more airway blockage and more infections. Over the course of many years, this damages the airways and eventually the lung tissue.

CF also affects other organs and systems in the body. For example:

  • In the pancreas, ducts become blocked, causing fibrosis (scarring) of the pancreas. This leads to reduced absorption of fat and vitamins. And it can also cause a type of diabetes referred to as “cystic fibrosis-related diabetes.”
  • In the digestive tract, intestinal secretions can be much thicker than normal. This causes blockages in the intestines and sometimes requires surgery.
  • In the liver, ducts can be blocked causing damage to the liver cells and cirrhosis.
  • In the reproductive tract, increased mucus can cause decreased fertility or infertility in both men and women.

How Serious Is Cystic Fibrosis?

CF is a life-threatening condition. There are about 30,000 people with cystic fibrosis in the United States and approximately 70,000 people worldwide. Approximately 1 in 30 Americans is a carrier. Sixty years ago, children diagnosed with CF usually did not survive childhood. However, due to improved care, the average life expectancy has been steadily increasing since the 1950s and is currently close to 40 years. Almost half of those affected with CF are now over 18 years of age. Although it is seen in all racial groups, it is most common in Caucasians, and rare in individuals from the Far East and Native Americans.

    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.


    Ask An Expert

    Questions about your lung health? Need help finding healthcare? Call 1-800-LUNGUSA.

    Get help
    We need your generous support

    Make a difference by delivering research, education and advocacy to those impacted by lung disease.

    What is LUNG FORCE?

    LUNG FORCE unites women and their loved ones across the country to stand together in the fight against lung cancer.

    Get involved
    Join the fight for healthy lungs and healthy air.
    Donate Now.