CFTR proteins are made by cells to transport water and particles such as chloride ions into or out of cells. This helps maintain a healthy balance of water and salt in the body.
CFTR proteins are made when cells receive instructions from the CFTR gene to produce them. But the CFTR gene can have errors, or mutations.
The tabs below help explain how CFTR proteins work and how CFTR gene mutations produce defective CFTR proteins.
CF is the result of 2 disease-causing CFTR gene mutations that produce defective CFTR proteins. These proteins are too few in number, don't work right, or both.
CFTR proteins in a person without CF
In a person without CF, the cell produces CFTR proteins that work correctly. At the cell surface, the proteins act as channels between the inside and outside of the cells. These channels open and close to allow water and particles such as chloride ions to flow into or out of the cells. This helps the body maintain a healthy balance of salt and water.
CFTR proteins in a person with CF
In a person with CF, there are either too few CFTR proteins at the cell surface, CFTR proteins at the cell surface that don't work correctly, or both.
Too few CFTR proteins:
CFTR proteins not working right:
As a result, water and salt can't flow freely into or out of the cells like they should. This reduced water and salt flow can eventually lead to thick, sticky mucus building up in the lungs and other parts of the body, as well as other symptoms of CF.
CFTR gene mutations affect CFTR proteins in 2 ways:
- Mutations can affect how proteins function, or how well they do their job
- Mutations can also affect the quantity, or how many proteins are at the cell surface
Some mutations can cause problems with both function and quantity at the same time.