What is Cystic Fibrosis?

Cystic fibrosis (CF) is a life-threatening, chronic condition that primarily affects the lungs and digestive system.

People with CF inherit a defective gene that causes a buildup of thick mucus in the lungs, pancreas and other organs. When mucus clogs the lungs, it can become very difficult to breathe.

CF affects about:


Children and adults
in the United States.


Children and adults in 94 countries.

An additional:


are symptomless carriers
of the defective CF gene.

Respiratory problems are the most serious and persistent complication for people with CF.

Normal Airway:

In healthy lungs, the airway is lined with a thin layer of mucus.

Airway with CF:

With cystic fibrosis, thick, sticky mucus blocks the airway.

Symptoms of CF

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

Salty-tasting skin

Wheezing or shortness of breath

Poor growth or poor weight gain

Small, fleshy growths in the nose, called nasal polyps

Frequent lung infections, both bacterial and fungal

Persistent coughing, at times with phlegm

Frequent greasy, bulky stools or difficulty in bowel movements

Elevated risk of diabetes

97-99% of men are born with congenital absence of the vas deferens

Genetics and Diagnosis

CF is caused by mutations in a gene that produces a protein called CFTR.

CFTR controls the flow of salt and water in and out of the cells in the lungs and pancreas.

To have CF, a person must inherit two copies of the defective gene — one 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 themselves. Each time two CF carriers have a child:


Chance the child
will have CF


Chance the child
will be a carrier but
will not have CF


Chance the child
will not be a carrier
and won’t have CF

There are

> 1,800 known mutations

of the CF gene. Because there are so many, most genetic tests only screen for the most common mutations.

Most children are now diagnosed with CF at birth through newborn screening.

More than


are diagnosed by the age of 2.

A doctor who sees the symptoms of CF will order a sweat test and/or a genetic test to confirm the diagnosis.

A sweat test measures the amount of salt in a person’s sweat.

A mild chemical and a small amount of electricity are placed on the skin (usually on the arm) to stimulate the sweat glands.

Sweat is then collected and the amount of chloride, a component of salt in the sweat, is measured.

A high level of chloride could mean that the person has cystic fibrosis. The sweat test is painless.

In a genetic test, a blood sample or cells from the inside of the cheek are taken and sent to a laboratory that specializes in genetic testing.

A genetic test is often used to confirm a diagnosis of CF if the results of a sweat test are not clear, but genetic testing is mostly used to find out if a person is a CF carrier.


Treating a complex condition like CF requires therapies that address problems in different parts of the body, especially the lungs and the digestive system.

CF Foundation-accredited care centers work closely with people with CF and their families to create individualized treatment plans.

Fortunately, medical advances have made cystic fibrosis care better today than ever before.

Each day, most people with cystic fibrosis typically:

Do some form of airway clearance to help loosen and get rid of the thick mucus that can build up in the lungs. Some techniques require help from others or respiratory therapists. Many people with CF use an inflatable vest that vibrates the chest at a high frequency to help loosen and thin mucus.

Take inhaled medicines — 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.

Take pancreatic enzyme supplement capsules with every meal and most snacks to improve absorption of vital nutrients. People with CF also usually take multivitamins.

CFTR (cystic fibrosis transmembrane conductance regulator) modulator therapies are designed to correct the malfunctioning protein made by the CFTR gene. Today, about 90% of people with cystic fibrosis will respond to highly effective CFTR modulator therapy. Work is ongoing to address the needs of the remaining 10% of non-modulated patients.

Additional therapies with varying mechanisms of action are moving through the drug development pipeline everyday.

In some cases, people with cystic fibrosis with end-stage organ disease may require solid organ transplantation, like lungs, liver, or kidney. People with CF who require transplants will be referred to specialized clinics by their CF care teams. The Boomer Esiason Foundation has invested heavily in technology to improve outcomes in transplanted patients.

Life expectancy for people with CF

Many different factors — for example, severity of disease and age at diagnosis — can affect an individual’s health and the course of the disease.

Recent research has shown that the severity of CF symptoms is based partly on the type of CF gene mutations a person has.

The CF Foundation Patient Registry collects information on the health of the more than



the median predicted age of survival for people born with CF


Thanks to tireless fundraising for research and care, an increasing number of people with CF are living well into adulthood and leading healthy lives, pursuing careers, getting married and having children of their own.

Is there a cure for CF?

While there currently is no cure for cystic fibrosis, the CFTR modulator class of medicines have proven to be life changing for thousands of people living with CF. Beyond that, supporting care has improved over the decades allowing many with CF to live very full lives.

Notable milestones for the CF Community

The annual incidence of organ transplant is rapidly decreasing across the cystic fibrosis community.

55% of adults with CF report full or part-time work, and 40% have a college degree

The number of adults with cystic fibrosis starting families has more than doubled over the past decade.

BEF continues to support cutting-edge research to address the root cause of CF and maintains a robust pipeline of potential therapies targeting the condition from every angle. Research to find a cure for CF has never been more promising.

Please visit our Financial Assistance page to learn more about assistance programs available to those with CF.