What Is Cystic Fibrosis? Here’s What To Know

Cystic fibrosis (CF) is a genetic disease that causes breathing difficulties, chronic digestive problems, and other symptoms. It’s caused by a gene mutation that causes thick, sticky mucus buildup in the lungs and other organs, causing damage over time.

Certain risk factors, like being of European descent, increase your chances of developing cystic fibrosis. CF is relatively rare: about 38,000 people in the United States are estimated to live with this condition.

CF is a chronic (long-term), progressive condition that worsens over time and causes severe complications. Once considered a fatal condition for children, current treatment options and therapies have improved prognosis a great deal. While life expectancy with CF is below average, many people with the condition now live well into adulthood and have a much better quality of life.

Cystic fibrosis occurs due to mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which regulates the production of the CFTR protein. The CFTR protein moves chloride ions out of your cells, ultimately helping to balance salt and water in your body.

Researchers have identified over 2,000 CFTR mutations, with most cases falling into five classes:

Type 1: Type 1 arises due to a genetic mutation that causes the production of the CFTR protein to stop too early. This leads to reduced levels of CFTR protein.Type 2: This is the most common type of mutation. The mutations change the shape of the CFTR protein, either adding or subtracting amino acids. As a result, less protein can reach and activate cells.Type 3: The CFTR protein serves as a “gate” for cells, allowing chloride (a component of salt) to pass through. The mutation limits its ability to open, trapping the chloride inside.Type 4: The CFTR protein has the right shape but isn’t functioning properly. Chloride ions attract water and cannot go outside cells, causing thicker mucus.Type 5: This type arises when the genetic mutation causes problems producing new CFTR proteins.

The symptoms of cystic fibrosis vary from person to person. However, CF often causes distinct signs in newborns and infants, affecting organs such as the lungs, intestines, pancreas, and others.

Symptoms in Newborns and Infants

CF symptoms often emerge within the first 6-8 months of life. Common signs include:

Abnormally salty skin
Meconium ileus (inability to pass stool for 24-48 hours after birth)
Vomiting
Fever
Redness and swelling
Prolonged jaundice (yellowing of the skin and eyes)
Repeated lung infections and coughing up mucus
Failure to thrive and lack of weight gain
Undescended testicles in babies assigned male at birth

Respiratory Symptoms

In adults, the mucus buildup caused by cystic fibrosis severely affects the lungs, eventually leading to scarring, cyst formation, and lung failure. Respiratory symptoms include:

Wheezing
Chronic cough
Coughing up thick mucus or blood
Frequent lung or sinus infections
Nasal polyps (growths in the nasal passages)

Digestive Symptoms

Cystic fibrosis mucus can also spread to the intestines, liver, and pancreas (an organ just behind your stomach), causing a range of symptoms, including:  

Constipation
Diarrhea
Greasy, foul-smelling stools
Excess mucus in stool
Abdominal or back pain
Nausea, vomiting, and bloating
Sudden weight loss, loss of appetite
Jaundice (yellowing of skin or eyes),
Dark urine
Pale-colored stool
Fever

Other Symptoms

Other organ systems of the body can also be affected, leading to additional symptoms. These include:

Male infertility due to abnormal development of the vas deferensJoint and muscular pain and swellingDigital clubbing (bulging of fingers or toes)Bluish-purple tint to the skin, often the lips, mouth, earlobes, and fingernails due to reduced lung functionScaly, itchy skin

Cystic fibrosis is caused by mutations in the CFTR gene, which regulates the formation of CFTR proteins. This protein moves chlorides (salt ions) out of cells, attracting liquid for lubrication. The mutations reduce this function, leading to thick mucus buildup throughout your body.

The symptoms of cystic fibrosis occur due to the buildup of excess mucus in the organs, particularly the lungs and digestive tract. This raises your risk of:

Infection (because bacteria can easily get caught in the mucus)Growths (cysts) and scar tissue (fibrosis) in the lungsTissue damage and blocked ducts (openings) in the pancreas, liver, or intestines

Risk Factors

Cystic fibrosis is hereditary, meaning it is due to a genetic mutation that’s passed down from parent to child. Therefore, a family history of cystic fibrosis is the only risk factor. The CFTR gene is recessive, so you only develop the disease if both parents have it. If only one does, then you don’t have symptoms but may still carry the faulty gene, raising the risk of passing cystic fibrosis to your children.

Other factors influence how severe the symptoms are, including:

Genetic mutations: The class of cystic fibrosis (type of CFTR mutation) influences severity. Classes 1 through 3 are more likely to become severe.Race: Cystic fibrosis affects one in 2,500-3,500 newborns of European descent. Other races or ethnicities are still at risk. One in 17,000 African American and one in 31,000 Asian American newborns have the condition.Activity level: Higher physical activity levels improve lung health, while an inactive lifestyle can lead to more severe cases.Smoking: Since smoking tobacco and breathing in second-hand smoke affects lung function, exposure to smoke can make symptoms worse.Age: While CF is present from birth, it worsens with age. The older you are, the more likely you’ll have severe symptoms and complications.

A CF diagnosis typically involves several steps. Most cases are diagnosed within the first few days of life or sooner, especially since genetic testing and newborn screenings are becoming more common.

The goal is to confirm the cause of any symptoms and rule out other conditions, such as asthma, lung infections, celiac disease (an inability to digest gluten), and other causes of failure to grow.

Diagnosis can involve:

Genetic testing/carrier screening: These are voluntary tests to examine your DNA and see if you’re a carrier of a faulty CFTR gene. If you and your partner are carriers, there is a 25% chance your child will have cystic fibrosis.Preconception or prenatal screening: Before or during pregnancy, you can choose to have a blood or saliva test for CFTR gene mutations.Universal newborn screening: Testing for a CFTR mutation is now part of the standard screening panel for US newborns. It is performed through a blood test in the first two to three days of life. It screens for elevated levels of immunoreactive trypsinogen (IRT), which may be a sign of cystic fibrosis.Sweat chloride test: This tests for high chloride levels in sweat, which can confirm a suspected case or detect a potential one.Imaging: Depending on the case, your healthcare provider may use X-ray or other imaging methods to evaluate the lungs, abdominal cavity, and intestines.  

There is no cure for cystic fibrosis, so treatment goals are to manage symptoms, support the function of the lungs and other affected organs, and prevent or manage associated diseases or complications.

This involves a multi-faceted approach guided by a CF-specific care team of pediatricians, pulmonologists (lung specialists), gastroenterologists (digestive system specialists), and nutritionists, among others.  

Airway Clearance Techniques

Airway clearance techniques (ACTs) loosen mucus so it can be expelled from the lungs via coughing or huffing. Performing ACTs helps manage mucus buildup in the lungs, improve lung function, and prevent infections.

Techniques include learning specific ways to breathe or cough, using high-frequency chest wall oscillation (a vibrating vest that loosens mucus), and doing chest physical therapy techniques.

Prescription Medications

Most people with CF take a variety of medications. Medications can be used to help promote better breathing, clear out mucus, fight underlying infections, and/or improve CFTR protein function. These include:

Antibiotics, orally or via intravenous (IV) injection, which fight off bacterial infectionsNon-steroidal anti-inflammatory drugs (NSAIDs), such as Advil (ibuprofen) and othersBronchodilators, which are inhaled medications that open up and relax the airwaysCFTR modulator drugs, including Kalydeco (ivacaftor), Orkambi (ivacaftor and lumacaftor), and Trikafta (elexacaftor, tezacaftor, and ivactafor)Digestive enzymes, which help break down food and improve digestion

Breathing Support

If the cystic fibrosis severely affects your or your child’s lungs, your healthcare provider may call for breathing support devices and therapies, including:

Oxygen therapy, which delivers oxygen via a face mask or tubes in the nose or windpipe (trachea)Pulmonary rehabilitation, which is a series of breathing and lung exercises supported by a physical therapist Ventilator support, which involves using a device to introduce moist air into your lungs through a mask or breathing tube   Extracorporeal membrane oxygenation, which pumps blood through artificial lungs to add oxygen and remove carbon dioxide, allowing your lungs time to heal and recover

Surgery

In severe and advanced cases, surgery may be option. Surgeons may perform a lung transplant for cases of lung failure due to cystic fibrosis. A liver transplant is an option for liver failure, another potential but less common complication.

Dietary Interventions

For digestive symptoms of cystic fibrosis, healthcare providers recommend a balanced, high-calorie diet that features:

2,500-3,000 calories a day for people assigned female at birth
3,000-3,700 calories for people assigned male at birth
Foods that are very high in healthy fat, such as olive oil, avocadoes, and nuts
Foods that are high in protein and pancreatic enzymes, which help your body absorb more nutrients from food
Vitamins A, D, and E

Since cystic fibrosis is a genetic condition, there’s no preventing it. If you’re planning on becoming a parent, you have the choice of taking a genetic test to detect mutated CFTR genes. This way, you can know the chances that you may pass the condition on to a child or have one who’s a carrier.  

Prenatal screening while you’re pregnant can also detect many—but not all—types of cystic fibrosis. However, this type of test does carry risks to the health of the fetus.

Cystic fibrosis causes severe complications and increases the chances of developing many other conditions, including:

Intestinal blockage: Mucus from cystic fibrosis can block the intestines, which can become a medical emergency.
Gallstones: The buildup can also block gallbladder ducts, leading to the development of gallstones (a hardened, pebble-like material).
Chronic respiratory failure: The mucus, scarring, and cysts due to cystic fibrosis can lead to respiratory failure, in which the lungs can’t get enough oxygen into the lungs and body.
Cystic fibrosis-associated diabetes: Diabetes—an inability to regulate blood sugar—is a complication that affects up to 50% of those with cystic fibrosis over the age of 30.
Liver diseases: Cystic fibrosis spreading to the liver can contribute to liver failure (an inability of the liver to function) and biliary cirrhosis (liver scarring due to blocked bile ducts).
Pancreatitis: Another digestive complication is pancreatitis (inflammation and infection of the pancreas).
Malnutrition: Your intestines absorb nutrients as part of digestion. The mucus caused by CF can affect this process, leading to insufficient absorption of calories and nutrients.

When researchers first identified cystic fibrosis in 1938, a diagnosis in a newborn usually gave them about a year to live. With modern therapies and an improved understanding of genetics, about half of babies with the condition today can expect to live into their 50s.

Promising therapies, including those that target the CFTR gene, are also on the horizon. These may prove to be a turning point in cystic fibrosis management. However, the emotional impact of living with the condition—or being the parent of a loved one with it—can be severe. Additional strategies for support include the following: