Defective CFTR protein
People with cystic fibrosis have CFTR proteins that do not work correctly
Although we know of over 2,000 different mutations in the
Depending on the type of each mutation, this may lead to decreased numbers of CFTR proteins at the cell surface, CFTR proteins that do not work correctly, or both.
When CFTR proteins do not work correctly the channels do not stay open long enough, do not open as often as they should or are too narrow.
When there are too few CFTR proteins at the cell surface this can be due to gene mutations that cause the CFTR building instructions to be made incorrectly, or read incorrectly, by the parts of the cell that build the CFTR protein. Other mutations can cause faulty proteins to be produced that are destroyed by the cell before reaching the cell surface, or proteins which are unstable and are removed too quickly from the cell surface.
Too few CFTR proteins:
CFTR proteins not working correctly:
Having too few CFTR proteins at the cell surface, or CFTR proteins that do not work correctly means water and molecules such as
Different mutations have different effects on CFTR protein channel functioning.
*CFTR = Cystic fibrosis transmembrane conductance regulator
US CF Foundation, Johns Hopkins University, The Hospital for Sick Children. The Clinical and Functional Translation of CFTR (CFTR2). Resources. Available at:
https://cftr2.org/resources. Accessed February 2022.
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Derichs N. Targeting a genetic defect: cystic fibrosis transmembrane conductance regulator modulators in cystic fibrosis. European Respiratory Review 2013; 22(127): 58 - 65.
Welsh MJ, Ramsey BW, Accurso F, Cutting GR. Cystic fibrosis: membrane transport disorders. In: Valle D, Beaudet A, Vogelstein B, et al. eds. The Online Metabolic & Molecular Bases of Inherited Disease. The McGraw-Hill Companies Inc; 2004: part 21, chap 201. www.ommbid.com.