Cystic fibrosis

Cystic fibrosis is an inherited disease of the mucus glands. It causes chronic, progressive damage to the respiratory system, chronic digestive system problems, and can affect other organs.

The signs and symptoms of this disorder are caused by the production of abnormally thick, sticky mucus in the body's organs. Problems with breathing are among the most serious symptoms. Mucus can obstruct the airways and cause bacterial infections in the lungs, leading to chronic coughing, wheezing, and inflammation. Over time, mucus buildup and infections lead to permanent lung damage, including the formation of scar tissue (fibrosis) and cysts in the lungs.

Most people with cystic fibrosis also have digestive problems. Mucus can block the ducts of the pancreas, preventing enzymes produced by that organ from reaching the intestines to help digest food. Problems with digestion can lead to diarrhea, malnutrition, and weight loss. Some babies with cystic fibrosis have meconium ileus, a blockage of the intestine that occurs shortly after birth.

Infertility, or the inability to conceive a child, is common in men with cystic fibrosis, but infrequent in women with the condition.

Cystic fibrosis is a common genetic disease affecting Caucasians (whites) in the United States. The disease occurs in 1 out of every 3,000 Caucasian births. It also affects other ethnic groups, but is much less common: 1 in 15,000 African Americans and 1 in 31,000 Asian Americans have the disorder.

Mutations in the CFTR gene cause cystic fibrosis.

The protein made by the CFTR gene forms a channel that controls the movement of salt and water into and out of cells. Mutations in the CFTR gene alter this protein in such a way that the channel is blocked. As a result, cells that line the passageways of the lungs, pancreas, and other organs produce the abnormally thick mucus characteristic of cystic fibrosis.

Other factors likely influence the course of the condition. For example, changes in genes other than CFTR might help explain why some people with cystic fibrosis are more severely affected than others. Most of these genetic changes have not yet been identified, however.

This condition is inherited in an autosomal recessive pattern, which means two copies of the gene must be altered for a person to be affected by the disorder. Most often, the parents of a child with an autosomal recessive disorder are not affected but are carriers of one copy of the altered gene.

You may find the following resources about cystic fibrosis helpful.

• NIH Publications - National Institutes of Health (2 links)
• MedlinePlus - Health Information (2 links)
• Genes and Disease - Genetic disorder summaries
• Educational resources - Information pages (3 links)
• Patient support - For patients and families (4 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

• Gene Reviews - Clinical summary
• Gene Tests - DNA tests ordered by healthcare professionals
• ClinicalTrials.gov - Linking patients to medical research
• PubMed - Recent literature
• OMIM - Genetic disorder catalog

See How are genetic conditions and genes named? in the Handbook.

The Handbook provides basic information about genetics in clear language.

• What does it mean if a disorder seems to run in my family?
• What are the different ways in which a genetic condition can be inherited?
• If a genetic disorder runs in my family, what are the chances that my children will have the condition?
• Why are some genetic conditions more common in particular ethnic groups?

These links provide additional genetics resources that may be useful.

• Genetics and health
• Resources for Patients and Families
• Resources for Health Professionals

autosomal ; autosomal recessive ; carrier ; channel ; chronic ; cysts ; digestion ; digestive ; digestive system ; duct ; enzyme ; gene ; infection ; infertility ; inflammation ; intestine ; mutation ; protein ; recessive ; respiratory ; sign ; symptom

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.