The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene

Understanding the Gene That Causes Cystic Fibrosis

The CFTR gene prevents the cell membrane from working properly.. BSIP/Universal Images Group/ Getty Images

As remarkable as it may seem, all the many problems experienced by patients with cystic fibrosis (CF) are caused by mutations in a single, large gene - the cystic fibrosis transmembrane conductance regulator (CFTR) gene, located on chromosome 7.

What Is the CFTR Gene?

The CFTR gene is responsible for regulating salt and water movement across cell membranes. Therefore, this gene controls the amount of water present in mucus, sweat, tears, saliva, and digestive enzymes.

What Is Different About the CFTR Gene in Someone With CF?

Cystic fibrosis occurs when the CFTR gene contains one of many possible mutations that prevent it from doing its job normally. In CF, secretions in the respiratory system, the gastrointestinal tract, and the biliary system do not contain enough water. The secretions become thick, viscous, and difficult to clear.

These thick secretions cause malabsorption of food, biliary obstruction, progressive problems in the liver and pancreas, obstruction of the airways, and chronic lung infections.

There are roughly 1500 known CFTR mutations, in six different categories, that can cause CF. Because of this variety of mutations, patients with CF will be affected in somewhat different ways. But in every case, the root cause is the same - a mutation in the CFTR gene.


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Drumm ML, Collins FS. Molecular biology of cystic fibrosis. Mol Genet Med 1993; 3:33.

Edited by Richard N. Fogoros, MD

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