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What is Cystic Fibrosis?

Cystic fibrosis (CF) is a complex, genetic disease, which affects the body's transport of electrolytes and fluids across cell membranes and the clearance of secretions from exocrine glands. Exocrine glands are present everywhere the body comes in contact with the external environment. These glands secrete substances such as sweat, mucus and digestive enzymes directly or through ducts. They also secrete and reabsorb electrolytes and other body fluids. Cystic fibrosis also causes the body to produce thick, sticky mucus. This happens because sodium and chloride (salt) are improperly transported within cell linings to their outer surfaces. This mucus obstruction interferes with how organs such as the lungs, pancreas, sweat glands, gastrointestinal tract, liver, and reproductive system function.

This mucus obstructs air passages in the lungs. It is very difficult to remove and causes infection, airway inflammation, and tissue damage. The thick mucus also causes blockages in the pancreas and prevents enzymes from reaching the intestines to help break down and digest food, poor absorption of the vitamins and nutrients in food leads to malnutrition. In children with frequent pulmonary infections, chronic lung disease changes and malnutrition, the onset of puberty may be delayed by an average of 1 to 4 years.

Cystic fibrosis does not affect the reproductive system in a life threatening or debilitating way. Also, the changes in the reproductive system affect men and women differently. Anatomical abnormalities occur in about 95–98% of males with cystic fibrosis. The vas deferens is atrophied or missing. This abnormality prevents the sperm from being delivered. Females with cystic fibrosis tend to have functional rather than anatomical reproductive problems. The cervical mucus becomes very thick and makes it difficult for the sperm to penetrate. However, it is possible for some cystic fibrosis patients are able to have children of their own. Females with good pulmonary and pancreatic function tend to have higher fertility rates than those that do not.

According to the Cystic Fibrosis Genetic Analysis Consortium, there are approximately 1006 CFTR mutations and 208 sequence variations. Depending on the genetic mutation, the disease varies considerably in severity. Some cases are very mild, and may not be diagnosed until adulthood.

Created: September 2003
Reviewed: May 16 2005
Revised: May 16, 2005

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