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Cystic fibrosis (CF)


Information relating to cystic fibrosis is reprinted with permission of PulmonologyChannel.


Cystic fibrosis (CF) is the most common fatal, inherited disease in the United States (see Statistics). CF causes the body to produce abnormally thick and sticky mucus in several different parts of the body, most prominently in the lungs and other parts of the respiratory system. It also affects the pancreas, leading to serious digestive problems.

CF alters the mucus secretions of the body’s epithelial cells. Epithelial cells make up the outside layer of tissue that lines every open surface of the body, inside and out, including the various tunnels and cavities in the lungs, urinary tract, liver, and reproductive tract. In patients with CF, the mucus that the epithelial cells secrete is much thicker and stickier than normal. It clogs the airways of the lungs, blocking the flow of air and making the tissue vulnerable to continual lung infections. It blocks the flow of pancreatic juices in the pancreas, impeding digestion and the absorption of fats and fat-soluble vitamins, leading to nutrition deficiencies and intestinal complications.

CF is a genetic disease resulting from the inheritance of a defective autosomal recessive gene (see Genetics of Cystic Fibrosis). A recessive gene is one that is expressed only when both copies of the gene are present, so a person with CF must have inherited the gene that causes CF from both parents. A person who has only one copy of the gene is known as a "CF carrier."

The defective gene that causes CF codes for a protein responsible for salt (sodium chloride) transport by the epithelial cells. There are several hundred possible mutations that can lead to CF symptoms. The severity of symptoms varies depending on the particular mutation. Patients with milder symptoms live longer.

Due to vast improvements in treatment, the expected life span of people with CF has increased dramatically. Before the mid-1960s, the median age of death of children with CF was 2 years. That means that one-half of babies born with CF died by the age of two. By the early 1990s, the median age of death had increased to 25 years. It is predicted that babies born with CF in the 1990s can expect to live for 40 years or more.

 

Statistics
According to the Cystic Fibrosis Foundation, about 30,000 Americans, 20,000 Europeans, and 3000 Canadians have CF. In the United States, about 12 million people are carriers, and every year 2500 babies are born with CF.

The disease affects all racial and ethnic groups, though it affects Caucasians with northern European ancestry more commonly than other populations. It is the most common autosomal recessive genetic disorder in Caucasians, occurring in about 1 out of every 1600 births. In African Americans, CF affects 1 in 13,000 babies; in Asian Americans, 1 in 50,000 are affected.

One in 22 Caucasians are carriers. Genetic testing can identify carriers, but the tests are only 80%-85% accurate because not all of the several hundred mutations that can cause CF are detectable.

 

Pregnancy and CF
Even though about 20% of women with CF are infertile, the good news is that when a woman with CF does get pregnant there is a very good chance that her baby will be healthy. About 90% of all pregnancies produce healthy babies, and women with CF generally can breastfeed their babies.

Though her baby may be healthy, outcomes for the mother vary, depending on the severity of her symptoms. Pregnancy can adversely affect lung disease and should be avoided if the woman is experiencing any type of lung dysfunction or cor pulmonale.

Follow-up
Frequent doctor visits
Patients should visit their doctor at least every 4 months.

Counseling and support groups
It is often a good idea for patients and/or families who are faced with the physical and emotional challenges of living with CF to seek professional counseling and support to better cope with the situation. The CF Foundation is a good place to start. The organization has local chapters across the United States and provides up-to-date research and treatment information. The foundation can provide patients and families with information about support groups in the area.

It may be especially important for the parents of babies or children with CF to seek support. Many parents feel guilty and responsible for their child’s disease. Seeking support and/or counseling can help relieve the parents’ guilt. By educating themselves and building a support network, parents can learn how best to interact with their child.

Genetic testing
Siblings and cousins of a patient with CF may want to be tested for the CF gene to determine if they are carriers or have CF themselves (if, for example, they have had chronic CF symptoms).

Sex life
People with CF can have a satisfying sex life. However, most men with CF are infertile, and women are usually less fertile than women without CF.

Self-management skills
Patients and parents should educate themselves about the disease by searching for resources available through the CF Foundation and by asking their doctors and other health providers about how to best care for themselves or their child.