What is cystic fibrosis exactly?

Inherited disease. Cystic fibrosis (CF) is an inherited disease that affects the cells lining the lungs, sinuses, intestines, spleen and liver. It prevents chloride ions from crossing the cell membranes properly. This can clog organ ducts. In the lungs, the extra mucus crushes the cilia and leads to more lung infections. Medications can help; in late-stage disease, lung transplantation may be life-saving.