CFTR Protein Defects

What are some of the defects that may affect cells that line the airway in the lungs?

CFTR protein defects cause CF

A mutation (that is, a change) in the CF gene may result in CFTR proteins that:

  • Don't work correctly
  • Don't get to the cell surface, where they are normally located
  • Don't get to the cell surface and don't work correctly

Different mutations can result in different defects and different levels of CFTR activity. This means that some people with CF may have some movement of chloride ions through CFTR proteins into and out of the cells and others may not have any.


When CFTR proteins don't work correctly, this results in the "gates" of the CFTR protein staying closed most of the time. Because the “gates” are closed, very few chloride ions move into or out of the cell.


In addition to CFTR proteins that don't open the way they should, some people with indicated mutations could have other CFTR protein defects. These defects can include fewer CFTR proteins that reach the cell surface. While KALYDECO helps to keep the gates open longer, it does not increase the number of CFTR proteins at the cell surface.

How do defects in CFTR proteins affect my lungs?

A mutation may result in defective proteins that don't work correctly, don't get to the cell surface where they are normally located, or both don't work correctly and don't get to the cell surface. CFTR protein defects can cause CF. Different mutations result in different defects.

Clogged Airway

When CFTR proteins don’t work the way they should, very few chloride ions are able to move into or out of the cells. This changes the balance of salt and water in the lungs, causing thick, sticky mucus to build up and affect how organs such as the lungs work.


What is KALYDECO® (ivacaftor)?

KALYDECO is a prescription medicine used for the treatment of cystic fibrosis (CF) in patients age 2 years and older who have at least one mutation in their CF gene that is responsive to KALYDECO.

Talk to your doctor to learn if you have an indicated CF gene mutation.

It is not known if KALYDECO is safe and effective in children under 2 years of age.

Important Safety Information

Who should not take KALYDECO?

Do not take KALYDECO if you take certain medicines or herbal supplements such as: the antibiotics rifampin (Rifamate®, Rifater®) or rifabutin (Mycobutin®); seizure medications such as phenobarbital, carbamazepine (Tegretol®, Carbatrol®, Equetro®) or phenytoin (Dilantin®, Phenytek®); or St. John’s wort.

Talk to your doctor before taking KALYDECO if you take any of these medicines or supplements.