[Skip to Content]

About Cystic Fibrosis

Cystic Fibrosis (CF) is a multi system inherited disease that affects approximately 30,000 individuals in the United States, and is usually diagnosed in infancy.

Cystic Fibrosis causes the exocrine glands in the body to function abnormally, producing thick, sticky secretions, which may plug up ducts and other passageways in the body. Mucous plugs most often occur in the lungs and intestines and can interfere with vital body functions, such as breathing and digestion.

The sweat glands are also affected in CF. The amount of salt (sodium and chloride) and potassium in the sweat is abnormally high. This may cause problems during periods of increased sweating.

Advances in treatment over the past few decades and exciting new research progress has made for promises of better things to come for patients with CF and their families that would not have been conceivable a short time ago. Most people are living well into adulthood and are enjoying the challenges of a normal life.

How it Happens

In the United States, about one person in every 30 carries the gene for CF. People who carry the gene have no symptoms typical of CF. Since a carrier has no symptoms of CF, we usually do not know the person is a carrier until he or she becomes the parent of a child with CF.

Cystic Fibrosis happens when two people who carry the gene meet and both transfer the gene during conception. Conception occurs when the egg from the mother unites with the sperm from the father. Both the egg and the sperm contain thousands of genes. Genes are characteristics that distinguish how a person will physically look, how tall she will be, and many health conditions. Every person probably carries seven to eight genes that could be associated with serious health problems. CF is one such health condition.

When both parents are carriers of the gene, each and every pregnancy has a:

  • One in four chance (25%)* chance that the child will be born with cystic fibrosis.
  • Two in four (50%)* chance that the child will be a carrier of the gene but not have cystic fibrosis.
  • One in four (25%)* chance that the child will not carry the gene and not have cystic fibrosis.

*These odds apply to each pregnancy, whether the parents already have children with CF or not.


This information was taken from the booklet An Introduction to Cystic Fibrosis for patients and families by Cunningham, MD, James C.& Taussig, MD, Lynn M., 1999, a tool that our center uses to help families understand CF.

Top