What is the cause of cystic fibrosis?

Cystic fibrosis is primarily caused by a genetic mutation in the CFTR gene, which encodes the cystic fibrosis transmembrane conductance regulator protein. This protein plays a crucial role in the regulation of salt and water movement in epithelial tissues. The mutation leads to the dysfunction of chloride channels, resulting in thick, sticky mucus production in various organs, particularly the lungs and pancreas.

This genetic mutation can be inherited in an autosomal recessive manner, meaning that an individual must receive two copies of the mutated gene—one from each parent—to manifest the condition. The resulting abnormality in ionic transport not only causes respiratory issues due to mucus buildup but may also affect digestive processes and sweat glands, leading to a range of symptoms characteristic of cystic fibrosis.

Factors such as acquired infections, environmental influences, and autoimmune disorders do not directly cause cystic fibrosis and are not related to its underlying genetic basis. While individuals with cystic fibrosis may experience infections and complications due to their underlying condition, these are consequences rather than causes of the disease.