What Is Cystic Fibrosis? What Causes Cystic Fibrosis?

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Main Category: Cystic Fibrosis
Article Date: 28 Apr 2009 - 12:00 PDT

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Cystic fibrosis (CF) is a chronic disease that affects organs such as the liver, lungs, pancreas, and intestines. It disrupts the body's salt balance, leaving too little salt and water on the outside of cells and causing the thin layer of mucus that usually keeps the lungs free of germs to become thick and sticky. This mucus is difficult to cough out, and it clogs the lungs and airways, leading to infections and damaged lungs. The hereditary disease eventually leads to disability and multisystem failure due to the effects this mucus. In addition to the difficulties breathing and serious lung infections, CF mucus affects digestion by obstructing the pancreas and stopping natural enzymes from helping the body to break down and absorb food.

What causes cystic fibrosis?

Cystic fibrosis is caused by a mutation in a gene called the cystic fibrosis transmembrane conductance regulator (CFTR), which serves an important function in creating sweat, mucus, and digestive juices. Only one copy of this gene is needed to prevent cystic fibrosis, and most people have two copies. However, if a person lacks at least one unaltered version of this gene that can produce a CFTR protein, cystic fibrosis will result.

Cystic fibrosis is a hereditary disease in that one can only get it if his or her parents both are carriers. A child must inherit two copies of the defective gene in order to have CF. A child with two parents who are carriers of the defective gene has a 25% chance of having cystic fibrosis and being a carrier of two defective copies of the gene, a 25% chance of not being affected nor a carrier of a defective copy of the gene, and a 50% chance of not being affected by CF but carrying one defective copy of the gene.

Who gets cystic fibrosis?

About 1 in 4,000 children in the United States are born with CF and some 30,000 children and adults are living with the disease. The prevalence is higher among Caucasian people - especially among western European populations. In fact, 1 in 22 people of Mediterranean descent carries one gene for CF, making CF the most common genetic disease in these populations. In addition, about 1 in every 31 Americans is a carrier of at least one copy of the defective gene.

The predicted median life expectancy for individuals with cystic fibrosis was 37.4 years in 2008.

What are the symptoms of cystic fibrosis?

Severity of the CF is governed by the type of gene mutation that the person has, and there are some 1,400 different types of mutation. Common symptoms include:

• Skin that tastes very salty
• Persistent coughing, often with phlegm or extra mucus
• Frequent lung infections, such as pneumonia and bronchitis
• Wheezing
• Shortness of breath
• Little weight gain and poor growth, even with a good appetite
• Frequent greasy, bulky stools or trouble with defecation
• Nasal polyps - small, fleshy growths in the nose

Cystic fibrosis is associated with several other symptomatic diseases and conditions. These include a variety of lung diseases and infections, problems with the gastrointestinal system such as blockages and malabsorption, diabetes, clubbing of fingers and toes, osteoporosis, poor growth, and infertility.

How is cystic fibrosis diagnosed?

The majority of cystic fibrosis diagnoses occur just after birth as part of a newborn screening. An additional sweat test or genetic test will be conducted in order to confirm the diagnosis.

A sweat tests consists of a small electrode placed on the skin that stimulates sweat glands to produce sweat. The sweat is then analyzed in a lab to test the amount of chloride (an ion found in salt). Chloride levels that are above a certain threshold indicate that the person has CF.

A genetic test usually begins with a blood sample or a cell sample taken from inside the cheek. The sample is sent to a lab that can test for the existence of a few of the most common genetic mutations indicative of cystic fibrosis.

Several tests are also used to monitor disease progression and identify any complications that may occur. These include X-rays and CAT scans, sputum examinations, lung function tests, and blood tests, among others.

How is cystic fibrosis treated?

There is no known cure for cystic fibrosis. However, quality and length of life have been improved over the years through proper nutrition, specialized medical care, and aggressive drug treatments and therapies. Treatments will vary from person to person based on the severity of the disease and the symptoms that are caused by the particular gene mutation. People with CF are almost always taking antibiotics in order to suppress the development of infections.

Much of cystic fibrosis treatment consists of methods to clear mucus from the airways. Often, the techniques use vibrations to help loosen the mucus in the lungs so it can be coughed out. There are also medications such as mucus thinners, antibiotics, anti-inflammatories, and bronchodilators that help breathing and assist in the expulsion of mucus.

Patients with CF will also take pills called pancreatic enzyme supplements before meals and snacks since the disease blocks pancreatic enzymes from getting into the intestines. These help CF patients to digest food and get proper nutrition.

Sometimes, when lung function is especially low, physicians will recommend a double lung transplantation. The future may see gene therapies that can place a healthy copy of the CFTR gene into affected cells.

Video - What is Cystic Fibrosis

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Written by - Peter Crosta M.A.
Copyright: Medical News Today
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