Cystic fibrosis

Cystic fibrosis results from changes in the cystic fibrosis transmembrane conductance regulator gene, usually abbreviated CFTR. The gene encodes a protein that helps regulate the movement of salt and water across cell surfaces. When the protein does not work properly, mucus contains less water and becomes thick and sticky; sweat also contains more salt than usual. A person generally develops CF after inheriting a disease-causing CFTR variant from each biological parent. Someone with one variant is usually a carrier and can pass it on, but does not ordinarily have the disorder. The range of CFTR variants helps explain why the condition's features and severity differ among individuals.

Thick mucus can obstruct airways, make lung infections more likely and contribute to lasting lung damage. In the digestive system, mucus can interfere with the pancreas and the release of substances needed to digest food, which may impair nutrient absorption and growth. CF can also affect other organs, including the liver and reproductive system. Symptoms vary: some appear early in life, while people with milder forms may not be recognized until later. CF is a lifelong, multisystem condition rather than solely a lung disease.

Newborn screening can identify infants who may have CF, and carrier screening can help people considering pregnancy understand the chance of passing on CFTR variants. Screening approaches vary and do not detect every variant. When CF is suspected, clinicians may use a sweat test and genetic testing as part of an evaluation. Screening results and symptoms are interpreted in the context of clinical assessment rather than serving as a substitute for it.

Care is individualized and often coordinated by a team of specialists. Treatment can include airway-clearance therapy, medicines to manage mucus and infections, nutritional and digestive support, and monitoring for complications. CFTR-modulator medicines act on the underlying protein defect, but they are suitable only for people with particular CFTR variants. Ongoing advances in treatment and disease management mean many people with CF now live into adulthood, though the condition continues to require long-term care.