Cystic Fibrosis (CF)

Cystic fibrosis (CF) is an inherited, life-threatening disorder that damages the lungs and digestive tract. It is caused by a defective gene that triggers the production of thickened mucus that clogs airways and blocks the secretion of digestive enzymes. Symptoms are progressive and often severe, and they may include breathing problems, recurrent lung infections, poor growth, male infertility, and chronic inflammation of the pancreas, liver, kidneys, and heart. While there is no cure for CF, there are treatments that can improve both the length and quality of one's life.

Understanding Cystic Fibrosis

Frequently Asked Questions

  • What causes cystic fibrosis?

    Cystic fibrosis is caused by a mutation (a change in the DNA sequence) of the cystic fibrosis transmembrane receptor (CFTR) gene. A defect in this gene, of which there are more than 2,000 known mutations, results in the abnormal accumulation of thick, sticky mucus in the lungs and digestive system. Two copies of the mutated CFTR gene must be inherited in order to get the disease.

  • How is cystic fibrosis inherited?

    Every person has two copies of the cystic fibrosis transmembrane receptor (CFTR) gene. If a person inherits two copies of the mutated CFTR gene, one from each parent, they will have cystic fibrosis. This means that cystic fibrosis is inherited in an autosomal recessive pattern.

  • Is cystic fibrosis contagious?

    No. Cystic fibrosis is not a contagious disease. Therefore, the disease cannot be contracted by kissing, hugging, holding hands, or coming into contact with the blood or bodily fluids of an infected person. The only way to get cystic fibrosis is by inheriting two abnormal cystic fibrosis genes, one from each parent.

  • How common is cystic fibrosis?

    Cystic fibrosis affects about 30,000 people in the United States and 70,000 people worldwide. Even though the disease is rare, about 1 in 30 Americans is a carrier of the abnormal gene that causes cystic fibrosis.

  • Is cystic fibrosis dominant or recessive?

    Cystic fibrosis is a recessive disease. This means that in order to get cystic fibrosis, a person needs to inherit the abnormal gene from both parents. If a person gets the abnormal gene from only one parent, they will not have cystic fibrosis—however, they may pass the gene on to their children.

Key Terms

Page Sources
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  1. Cystic Fibrosis Foundation. About cystic fibrosis.

  2. Cystic Fibrosis Foundation. Basics of the CFTR protein.

  3. National Human Genome Research Institute. Genetic disorders. Updated May 18, 2018.

  4. Cystic Fibrosis Foundation. Sweat test.

Additional Reading