What Is Cystic Fibrosis?

Cystic Fibrosis (CF) is an inherited condition characterized by the production of abnormally thick, sticky mucus, particularly in the lungs and digestive system. While it is normal to have mucus lining the organs of the respiratory, digestive, and reproductive systems in order to lubricate and protect them, in individuals with CF this mucus is thick and sticky. This abnormal mucus results in the clogging and obstructing of various systems in the body. CF is a chronic condition that worsens over time. CF is caused by mutations in the CFTR gene.

Most individuals with CF experience breathing problems and frequent lung infections that lead to permanent lung damage such as scarring (fibrosis) and sac-like growths (cysts). The pancreas, an organ that produces insulin and digestive enzymes, is often affected by CF. The sticky mucus caused by CF can block ducts which ferry enzymes from the pancreas to the rest of the body, resulting in problems such as diarrhea, malnutrition, and poor growth. Infertility, particularly in men, and delayed puberty are also common among people with CF.

The severity of symptoms varies from person to person, even among individuals with the same mutations. Most cases of CF are diagnosed in early childhood. However, in general, individuals with two classic mutations are more likely to have a severe form of the disease including problems with the pancreas, while individuals with one classic and one non-classic or individuals with two non-classic mutations are more likely to have a milder form of the condition and may avoid problems with the pancreas.

Mutations in the same gene that causes CF can result in a condition in males called congenital absence of the vas deferens (CAVD). In CAVD, the vas deferens (a reproductive organ involved in sperm transport) is improperly formed, leading to infertility.

How Common Is Cystic Fibrosis?

According to the National Institutes of Health, CF is the most common deadly inherited condition among Caucasians in the United States, with a prevalence of 1 in 3000 in individuals of Caucasian or Ashkenazi Jewish descent. CF is rarer in other groups. The prevalence is 1 in 8,300 in Hispanics, 1 in 17,000 in African Americans, and 1 in 30,000 in Asians.

How Is Cystic Fibrosis Treated?

FDA approved medications are available for individuals with certain CFTR mutations. There are also many other options for treating the symptoms in everyone with CF, regardless of the mutation present. Because thick mucus can build up in the respiratory system, it is important to keep the patient's airways open in order to ease breathing and prevent infection. This can be accomplished with various prescription drugs as well as by physically loosening mucus by pounding on the patient's back in a prescribed way. This treatment, known as "postural drainage and chest percussion" must be performed by someone other than the affected person, and is typically done at least once daily. As respiratory infections occur, physicians typically prescribe antibiotics.

Physicians will also monitor the digestive system to ensure that the patient is getting proper nutrition. Enzymes or vitamin supplements may be prescribed. Both the respiratory and digestive systems of an individual with CF must be monitored regularly by a medical team.

Surgery may be needed to correct certain problems caused by CF and lung transplants are an option for some individuals.

What Is the Prognosis for an Individual with Cystic Fibrosis?

Thanks to improved treatments and a better understanding of the condition, the average life expectancy for individuals with CF who live to adulthood is near 40 years. Children born with CF today who receive early treatment may live even longer.

Other names for
cystic fibrosis

  • CFTR-related disorders
  • Fibrocystic disease of pancreas
  • Mucoviscidosis


  • Moskowitz, et al., 2008, Genet Med, 10(12):851-68, PMID: 19092437
  • OMIM: Online Mendelian Inheritance in Man, OMIM [219700], 2016, http://www.omim.org/219700
  • Ong et al., 2017, https://www.ncbi.nlm.nih.gov/books/NBK1250/
  • Sosnay, et al., 2017, J Pediatr, 181S:S27-S32.e1, PMID: 28129809