Cystic Fibrosis


The Facts

Cystic fibrosis (CF) is an inherited (genetic) disease in which excess mucus clogs the lungs, prevents food from being digested, and damages the reproductive system. It is the most common life-threatening genetically inherited disease affecting Caucasians. About 30,000 children and adults in the United States, mostly Caucasians, have cystic fibrosis.

In CF, an abnormal protein called CFTR is produced. This protein changes the way chloride (a component of salt, which is also called sodium chloride) moves in and out of cells. This affects the balance between salt and water in the body, making the mucus that lines the lungs, pancreas, and other organs thicker and stickier.

CF affects all the body's exocrine glands. These glands create chemicals necessary for proper functioning of the body. The pancreas, for example, is an exocrine gland that provides digestive enzymes for the stomach. The sweat glands provide liquid to cool the skin. In CF, some glands produce abnormal substances. The sweat glands, for example, release high levels of salt. Other glands, like the pancreas, become plugged with mucus. Because it affects so many organs in our body, CF is usually diagnosed early in childhood.

The tables below show your risk of being a CF carrier based on which family members have CF or on your ethnicity:

Relative with CF Your carrier risk
Parent or child 1 in 1 (100%)
Siblings 2 in 3 (67%)
Niece or nephew 1 in 2 (50%)
Aunt or uncle 1 in 3 (33%)
Cousin 1 in 4 (25%)


Ethnicity Carrier risk
Caucasian (white, European ancestry) 1 in 25
Ashkenazi Jewish 1 in 25
Hispanic 1 in 46
African American 1 in 65
Asian 1 in 90

Thanks to good research, better and more medications, and early diagnosis, people with CF are living longer, fuller lives.


CF cannot be "caught" like a cold or the flu. It's genetic and is caused by inheriting two copies of the same abnormal gene, one from each parent. People who get one defective and one normal copy of the gene are said to be "carriers" of the CF gene. Carriers don't get CF, but they have the abnormal CF gene that can be passed on to their children.

If both parents are carriers, their children have a 1 in 4 chance of getting the disease, a 1 in 2 chance of being carriers, and a 1 in 4 chance of being normal. Boys and girls are equally likely to have CF.

Researchers have also noticed higher levels of some essential fatty acids in people with CF. The role of these fatty acids is still unknown.

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The contents of this health site are for informational purposes only. Always seek the advice of your physician or other qualified healthcare provider regarding any questions you may have about a medical condition.

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