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Genetic and Rare Diseases Information Center (GARD)

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Cystic fibrosis

Other Names for this Disease
  • CF
  • Mucoviscidosis
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Your Question

Are carriers of cystic fibrosis at a higher risk for other health conditions?

Our Answer

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Are carriers of cystic fibrosis at a higher risk for other health conditions?

Mutations in CFTR have been associated with a range of conditions, including obstructive azoospermia, idiopathic pancreatitis, disseminated bronchiectasis, allergic bronchopulmonary aspergillosis, atypical sinopulmonary disease, and asthma. Some of these conditions are associated with carrying a single CFTR gene mutation, while others are associated with carrying two CFTR gene mutations. In some cases the CFTR gene mutation is thought to be causitive, in other cases the reason for the association is not clear.[1] 

On the otherhand, it may be possible that a CFTR gene mutation provides a health advantage. The carrier frequency of cystic fibrosis in Caucasians is relatively high (i.e., approximately 1 in 29 are carriers).[2] As a result much thought has been given to why this is so. We know that the protein made from the CFTR gene (also called CFTR) is required for chloride (and water) secretion in the intestines and in the upper airways of the lungs. One theory suggests that cystic fibrosis carriers are better protected against death from cholera and possibly other diarrheal diseases. A second theory is that carriers are better protected against infectious diseases like Salmonella typhi (typhoid fever) which uses CFTR to enter and infect cells. Another theory supposes that certain carriers (i.e., people who carry a single Delta 508 mutation) may be better protected against bronchial asthma.[3][4] While theories exist, the precise reason for the high carrier frequency of CFTR gene mutations in people of Northern European ancestry is not known.
Last updated: 5/6/2010

  • Nussbaum, McInnes, Willard. Thompson & Thompson Genetics in Medicine. Philadelphia, PA: Saunders; 2004;
  • Watson MS et al., . Cystic Fibrosis Population Carrier Screening: 2004 revision of American College of Medical Genetics mutation panel. Genetics in Medicine. 2004;
  • Goodman BE, Percy WH. Adv Physiol Educ. 2005 Jun; Accessed 4/23/2010.
  • Schroeder SA, Gaughan DM, Swift M. Protection against bronchial asthma by CFTR F508 mutation: a heterozygote advantage in cystic fibrosis. Nat Med. 1995;