About Cystic Fibrosis Cystic fibrosis (CF) is a life-shortening, inherited disorder that occurs most frequently among Caucasians. CF affects the body's exocrine (outwardly secreting) glands that produce mucus. In patients with CF, mucus becomes thick and sticky and often plugs ducts and channels, especially in the pancreas, inhibiting the flow of pancreatic digestive enzymes to the small intestine. Without these enzymes, the body cannot properly digest fats, proteins and carbohydrates. The resulting nutrient malabsorption interferes with weight gain and slows growth.