About Cystic Fibrosis

What Is Cystic Fibrosis?

Cystic fibrosis is a progressive, genetic disease that affects the lungs, pancreas, and other organs. 

There are close to 40,000 children and adults living with cystic fibrosis in the United States (and an estimated 105,000 people have been diagnosed with CF across 94 countries), and CF can affect people of every racial and ethnic group.

There are many misconceptions about CF. Learn the facts on our page, Dispelling Misconceptions About Cystic Fibrosis.

In people with CF, mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause the CFTR protein to become dysfunctional. When the protein is not working correctly, it’s unable to help move chloride — a component of salt — to the cell surface. Without the chloride to attract water to the cell surface, the mucus in various organs becomes thick and sticky.

In the lungs, the mucus clogs the airways and traps germs, like bacteria, leading to infections, inflammation, respiratory failure, and other complications. For this reason, avoiding germs is a top concern for people with CF.

In the pancreas, the buildup of mucus prevents the release of digestive enzymes that help the body absorb food and key nutrients, resulting in malnutrition and poor growth. In the liver, the thick mucus can block the bile duct, causing liver disease. In men, CF can affect their ability to have children.

Learn how the cystic fibrosis transmembrane conductance regulator affects the digestive system.

Understand how the cystic fibrosis transmembrane conductance regulator (CFTR) affects the GI system.

Today, because of improved medical treatments and care, more than half of people with CF are age 18 or older. Many people with CF can expect to live healthy, fulfilling lives into their 30s, 40s, and beyond. 

Read the Foundation's Patient Registry Reports.

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
  • Nasal polyps
  • Chronic sinus infections
  • Clubbing or enlargement of the fingertips and toes
  • Rectal prolapse
  • Male infertility

Learn more about CF — from diagnosis to living with the disease as an adult — in "An Introduction to Cystic Fibrosis: For Patients and Their Families," or watch the video series.


Jay, a 6-year-old with CF

Listen to CF clinicians explain:

  • Which body parts are affected by CF
  • Common CF symptoms
  • How CF is treated
Genetics and Diagnosis

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.

People with only one copy of the defective CF gene are called carriers, but they do not have the disease. Each time two CF carriers have a child, the chances are:

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

The defective CF gene contains a slight abnormality called a mutation. There are more than 1,700 known mutations of the disease. Most genetic tests only screen for the most common CF mutations. Therefore, the test results may indicate a person who is a carrier of the CF gene is not a carrier.

Diagnosing cystic fibrosis is a multistep process, and should include a:

Although most people are diagnosed with CF by the age of 2, some are diagnosed as adults. A CF specialist can order a sweat test and recommend additional testing to confirm a CF diagnosis.

Read the CF Foundation’s clinical care guidelines for diagnosing CF.

I grew up wondering why I felt sick every day. As doctors suggested unlikely diseases, such as hormonal disorders, kidney disease, lupus, and depression, I felt I was further from an answer. Then, my ENT suggested CF, a disease I had never heard of. As he described what he knew about CF, it matched all of my symptoms and promised the answer I had been looking for my whole life.” — Katie K., an adult with CF, from the Community Blog

According to the Cystic Fibrosis Foundation Patient Registry, in the United States:

  • There are close to 40,000 children and adults living with cystic fibrosis in the United States (and an estimated 105,000 people have been diagnosed with CF across 94 countries).
  • Approximately 1,000 new cases of CF are diagnosed each year.
  • More than 75 percent of people with CF are diagnosed by age 2.
  • More than half of the CF population is age 18 or older.

Did you know?

More than half of the cystic fibrosis population is over 18.

What to Expect

Cystic fibrosis is a complex disease. The types of symptoms and how severe they are can differ widely from person to person. Many different factors can affect a person's health and the course the disease runs, including your age when you are diagnosed.

The Outlook

Tremendous advancements in specialized CF care have added years and improve the quality of the lives of people with cystic fibrosis. During the 1950s, a child with CF rarely lived long enough to attend elementary school. Today, many people with CF achieving their dreams of attending college, pursuing careers, getting married, and having kids.

Watch this video to see how we "count our success in lives" as we continue writing the next chapter in CF together.

Although there has been significant progress in treating this disease, there is still no cure and too many lives are cut far too short.

Managing CF

The types of CF symptoms and how severe they are can differ widely from person to person. Therefore, although treatment plans can contain many of the same elements, they are tailored to each person's unique needs.


Tré, a 24-year-old with CF, wearing his vest.

People with CF and their families have expertise in how the disease affects them and how their daily lives affect the way they approach their care. By acknowledging each other's expertise, people with CF, their families, and clinical care teams can work together to develop treatment plans that align personal life goals with health goals.

“My doctor and I decided to come up with a plan that would work for me. We were able to negotiate a deal so that I was doing more treatments than I had been, but I wasn’t just sitting at home hooked up to machines.” — Betsy Sullivan, a teenager with CF, from the CF Community Blog

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.
  • 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 and 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.
  • An individualized fitness plan to help improve energy, lung function, and overall health
  • CFTR modulators to target the underlying defect in the CFTR protein. 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.

Support From the CF Foundation

The CF Foundation supports people with CF by:

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


When a group of parents started the Cystic Fibrosis Foundation in 1955, there were no treatments for cystic fibrosis. These parents set their sights high, to:

  • Advance understanding of this little-known disease
  • Create new treatments and specialized care for their children
  • Find a cure

In the following years, the fundraising and commitment of the CF community has enabled the Foundation to support fundamental research in the laboratory that has led to groundbreaking discoveries, including identifying the gene and protein responsible for cystic fibrosis. By expanding our knowledge of the underlying biology of the disease and its effect on the body, researchers have paved the way for creating new treatments.

The Foundation's steadfast commitment to advancing CF research has helped enable more than a dozen new treatments for the disease. We have made incredible progress, including the approvals by the U.S. Food and Drug Administration (FDA) of Kalydeco® (ivacaftor), Orkambi®  (lumacaftor/ivacaftor), Symdeko® (tezacaftor/ivacaftor), Trikafta® (elexacaftor/tezacaftor/ivacaftor), Cayston® (aztreonam), and TOBI® (tobramycin).

Watch this video to see how clinical research has made a difference in the lives of people with CF.

Research by dedicated scientists and clinicians from a wide range of disciplines advances our understanding of cystic fibrosis every day, helping to shape clinical care practices for people living with the disease for years to come. These include studies conducted using patient data in the CF Foundation's Patient Registry, which are helping us identify trends and track the effectiveness of treatments.

The Foundation is supporting the best research here and abroad to improve the quality of life of people with CF today and increase the speed of innovative research and drug development to add tomorrows. Two major initiatives are helping with this mission.

To make meaningful progress against infections, we established the five-year Infection Research Initiative to help improve the detection, diagnosis, prevention, and treatment of infections. From 2018 through 2023, we invested more than $170 million to fund research and the development of new treatments. We also conducted a comprehensive review of our research portfolio, identifying and filling gaps, evaluating our investments, and recalibrating our infection research strategy. This initiative helped us set the agenda going forward for a robust infection research program so that we can continue to meet the needs of the CF community.

The second major initiative is the Path to a Cure, an ambitious research agenda to deliver treatments for the underlying cause of the disease and a cure for every person with CF. The Foundation is challenging potential collaborators to submit proposals that will accelerate the pace of progress in CF drug discovery and development and intends to allocate $500 million to the effort through 2025. The Path to a Cure centers around two core strategies to address the underlying cause of CF: restoring CFTR protein when none exists and fixing or replacing the underlying genetic mutation to address the root cause of CF. 

By pursuing these bold strategies and others, the CF Foundation continues to build a robust pipeline of potential new therapies that fight the disease from every angle. Learn more about the CF Foundation's key research programs:

  • Research We Fund: See a snapshot of how the CF Foundation is funding cystic fibrosis research.
  • CF Foundation Therapeutics Laboratory: Based in Lexington, Mass., the CF Foundation Therapeutics Laboratory identifies and tests potential groundbreaking therapies for CF, readying them for further development.
  • Therapeutics Development Network: The Therapeutics Development Network is the largest CF clinical trials network in the world. It provides the resources and support for studies that are leading to important new therapies and better treatments.
  • Drug Development Pipeline: Discoveries from the laboratory are being turned into potential drugs that attack both the symptoms of CF and the cause — a faulty gene that makes a defective protein.
  • Research Centers: These CF "think tanks" are located at top universities and medical schools across North America, where scientists from many disciplines are brought together to combine their expertise to find a cure for CF.
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Diagnosis | Intro to CF
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