Cystic Fibrosis

Cystic Fibrosis Image

Cystic fibrosis (CF) is a genetic disease affecting the mucus glands of the lungs, pancreas, liver, sinuses, intestines and sex organs. Mucus, which is normally thin and watery, usually keeps tissues moist. Those who develop CF, however, have very thick mucus, which results in frequent lung infections. This mucus can block ducts leading to the pancreas as well. Sweat glands are also affected.

Signs and Symptoms of Cystic Fibrosis

Genetic tests can identify individuals with a mutated gene even before they are born. Newborn genetic screening tests can detect the disease as well. Sweat tests must be performed after birth, however, to determine if the individual is a carrier or has the disease.

Symptoms and severity differ from person to person. One individual may have terrible lung and digestive disorders. Others may not have any symptoms until later in life. Some symptoms include:

  • a bloated feeling
  • a deficiency in the fat-soluble vitamins A, D, E and K
  • greasy and/or bulky stools
  • intestinal gas
  • malnutrition
  • poor growth
  • shortness of breath
  • stomach pain or discomfort.

In advanced cases, lung and pancreatic disorders cause many problems. Mucus in the lungs harbors bacteria that cause lung infections and the mucus blocks airways, making breathing difficult. Respiratory failure is a major threat.

Ducts in the pancreas may be blocked by mucus. The pancreas normally produces digestive enzymes that break down food in the intestines. If the ducts are blocked, proteins and fats are not metabolized correctly. When this happens, the person suffers from stomach and intestinal difficulties, malnutrition and abnormal stools.

People who have CF have sweat which is five times as salty as that of a healthy individual. Their mineral balance can be upset if they perspire and lose large quantities of sodium, which is very important in the body’s normal functions. This loss can result in a heat emergency or abnormal heart rhythms.

What Causes Cystic Fibrosis

Medical research has established a genetic link to cystic fibrosis. A single gene on chromosome 7 makes a protein called the cystic fibrosis transmembrane conductance regulator (CFTR). This gene is responsible for making sweat, mucus and digestive juices. The protein controls chloride ions going in and out of cells.

People who have cystic fibrosis have a mutation in the CFTR gene. This means that chloride ions are not capable of getting through the membrane of the cells. In most cases, however, the CFTR protein is missing. The shortened version is identified by the body and destroyed.

CF is inherited and is not contagious. It is a recessive disorder, meaning that people with one normal gene and one mutated gene are carriers of the disease. Offspring must inherit the mutated gene from each parent to have symptoms. Offspring of two parents who are carriers have a 25 percent chance of developing the disease.

Treatment for Cystic Fibrosis

Treatment involves the use of antibiotics and clearing the mucus out of the lungs. Patients are prescribed enzymes to help them digest their food and obtain nutrients.

Surgery is sometimes necessary to clear obstructions. Lung transplants may be required if tissue damage is too severe.

Progress Toward a Cure

There is no cure for CF. A cystic fibrosis prognosis is not good. But research gives hope of an increasing life expectancy of people with CF. Recent developments in treating and curing the disease are under development. Gene therapy that involves placing a normal CFTR gene in the infected cells may be available in the near future.

Some other developments toward a cure target the metabolic pathways involved in the disease. These include:

  • correcting problems with the lining of the lungs to prevent infections
  • improving the mucus so it is not so thick
  • new antibiotics
  • new medications to reduce the toxic effects of the inflammatory immune response.

Resources

National Institutes of Health. (2008). What is cystic fibrosis? Retrieved December 16, 2008, from the National Institutes of Health Web site: http://www.nhlbi.nih.gov/health/dci/Diseases/cf/cf_what.html.

Your Genes Your Health. (n.d.). Cystic fibrosis. Retrieved December 16, 2008, from the Your Genes Your Health Web site: http://www.ygyh.org/cf/inherited.htm.