Cystic fibrosis is a genetic condition that causes the lungs and digestive system to become clogged with thick sticky mucus. Cystic fibrosis usually begins in childhood and includes symptoms such as a persistent cough, recurring chest and lung infections and poor weight gain. Although there is no cure for cystic fibrosis, treatments can make the condition easier to live with, and treatment advances are allowing people with Cystic Fibrosis to live longer.