Cystic fibrosis is a life-threatening disorder that causes severe damage to the lungs and digestive system.

An inherited condition, cystic fibrosis affects the cells that produce mucus, sweat and digestive juices. These secreted fluids are normally thin and slippery. But in cystic fibrosis, a defective gene causes the secretions to become thick and sticky. Instead of acting as a lubricant, the secretions plug up tubes, ducts and passageways, especially in the lungs and pancreas.

Cystic fibrosis is most common in white people of Northern European ancestry, but also occurs in Hispanics, African-Americans and some Native Americans. It is rare in people of Asian and Middle Eastern origin.

Although cystic fibrosis requires daily care, most people with the condition are able to attend school and work, and have a better quality of life than in previous decades. Recent improvements in screening and treatments mean most people with cystic fibrosis now live into their 20s and 30s, and some are living into their 40s and 50s. mayoclinic.org

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