Cystic Fibrosis

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Also known as: CF

What is cystic fibrosis?

Cystic fibrosis (CF) is an inherited condition that causes the production of thick, sticky mucus, which affects lung function, leads to recurrent respiratory infections, blocks the release of pancreatic enzymes, and inhibits the digestion of protein and fat. Most people with CF are diagnosed in early childhood and require daily therapies to loosen and remove excess mucus as well as supplements to get adequate nutrition. Those affected often require close monitoring and prompt treatment of infections to help preserve lung function.

CF is a relatively common genetic disease caused by mutations (disease-causing variations in the DNA) in a gene located on chromosome seven. This gene is responsible for the normal production of a protein called cystic fibrosis transmembrane conductance regulator (CFTR). Variations in this gene lead to reduced, absent, or defective CFTR production, causing CF. More than 1,500 different CF mutations have been identified, although some are much more common than others.

CF is a recessive genetic disease. This means that a person with CF must inherit two defective CF genes -- one from each parent. An individual with one normal gene and one abnormal gene is a CF carrier. Carriers do not have symptoms and are not ill, but they may pass a copy of their abnormal gene on to their children. Both biological parents must either be carriers or have CF themselves in order for their child to have CF. The risk associated with carrying an abnormal CF gene can be generally associated with a person's ethnicity. Caucasians from Northern Europe and Ashkenazi Jews have the highest incidence of CF with 1 in 20-25 individuals being CF carriers.

Individuals with CF exhibit absent or defective production and function of CFTR, leading to abnormal electrolyte and water movement in and out of the epithelial cells. This, in turn, leads to thick, sticky mucus in the lungs and pancreas that promote respiratory infections and/or obstructed pancreatic and liver ducts, and impaired protein digestion. The majority of adult males with CF are also infertile due to missing or underdeveloped vas deferens, the tubules that transport sperm from the testes. Most people with CF develop respiratory and pancreatic symptoms early in life, although symptom severity varies from person to person, even in those carrying the exact same mutations.

CF is one of the most common recessive genetic disorders in the U.S. It is estimated that 30,000 Americans are living with CF and approximately 1,000 new cases are diagnosed every year. Currently, there is no prevention or cure, only treatment of symptoms. However, research is being conducted to enhance treatments and to develop a cure. Great strides in this effort have been made over the past ten years, which are allowing some people with CF to live longer, with improved quality of life.

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