Cystic Fibrosis, or CF, is a genetically-inherited progressive respiratory disease that damages the lungs and digestive systems. As the disease progresses, frequent infections limit and reduce the ability to breathe. The defective gene causes production and buildup of thick mucus in the lungs, pancreas and other organs, due to a defective gene that produces a protein called the CFTR. Symptoms may include frequent lung infection, a persistent cough that produces thick mucus, breathlessness, intolerance to exercise, and frequently inflamed sinuses or nasal passages. Due to the seriousness of CF, it is standard now for all newborns to be screened for it. CF is a life-threatening disease that can be treated to ease the symptoms, but ultimately cannot be cured.