Cystic Fibrosis: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medically Reviewed on 6/1/2017

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.


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

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

Medically Reviewed by a Doctor on 6/1/2017

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