Cystic Fibrosis: Symptoms & Signs

Medically Reviewed on 9/10/2019

Symptoms of cystic fibrosis mainly involve the lungs, pancreas, sex organs, intestines, and sinuses and arise from abnormal mucus that is unusually thick and sticky. The mucus buildup in the lungs leads to repeated infections with coughing, production of thick sputum, shortness of breath, wheezing, nasal congestion, and a decreased tolerance for exercise or physical activity. The airway symptoms place those affected at risk for pneumonia and sinusitis. Other symptoms of cystic fibrosis include

  • fatty, foul-smelling stools,
  • constipation, and
  • poor growth in children.

Malnutrition and vitamin deficiency can arise because pancreatic enzymes may not reach the intestine. Abdominal pain and swelling can occur. Cystic fibrosis also causes the sweat to be excessively salty and can cause infertility in men.

Cause of cystic fibrosis

Cystic fibrosis is caused by a mutation in the CF gene on chromosome 7. The protein coded by the CF gene is known as the cystic fibrosis transmembrane regulator (CFTR). The defect in the CFTR protein leads to disruption of chloride channels on cells, which in turn causes the production of abnormal mucus secretions.

Other cystic fibrosis symptoms and signs

Subscribe to MedicineNet's Children's Health & Parenting Newsletter

By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time.

Sharma, Girish D. "Cystic Fibrosis." June 8, 2016. <>.

United States. National Heart, Lung, and Blood Institute. "What Is Cystic Fibrosis?" Dec. 26, 2013. <>.