Cystic fibrosis (CF) is an inherited
disease that causes the body to produce mucus that's extremely thick and sticky.
The mucus is thicker than normal because CF affects cells in the epithelium
(pronounced: eh-puh-THEE-lee-um), the layer of cells that lines the passages in the
In a person who does not have CF, the epithelial cells produce a thin, watery mucus
that acts like a lubricant and helps protect the body's tissues. In someone with CF,
however, the thicker mucus doesn't move as easily. This thick, sticky mucus clogs
passages in many of the body's organs and infection sets in.
The two organs most affected are the lungs and pancreas,
where the thick mucus causes breathing and digestive problems. The thicker mucus has
trouble moving out of the lungs, so bacteria can remain and cause infections.
The thick mucus also is in the pancreas— an organ
that produces proteins called enzymes that flow into the intestine
to support the body's digestion process. Because the mucus can block the path between
the pancreas and the intestines, people with CF have trouble digesting food and getting
the vitamins and nutrients they need from it.
CF can also affect the liver, the sweat glands, and the reproductive organs.
What Causes CF?
Approximately 30,000 people in the United States have been diagnosed with CF, which
affects both males and females. It's not contagious, so you can't catch CF from another
Cystic fibrosis is an inherited disease caused by mutations (changes) in a gene
on chromosome 7, one of the 23 pairs of chromosomes that children inherit from their
parents. CF occurs because of mutations in the gene that makes a protein called CFTR
(cystic fibrosis transmembrane regulator). A person with CF produces abnormal CFTR
protein — or no CFTR protein at all, which causes the body to make thick,
sticky mucus instead of the thin, watery kind.
People who are born with CF have two copies of the CF gene. In almost all people
born with CF, one gene is received from each parent. This means that the parents of
kids with CF are usually both CF carriers — that is, they have one normal
and one defective gene — but the parents may not have CF themselves because
their normal gene is able to "take over" and make the necessary CFTR protein.
Each child born to parents who are both CF carriers has a 1 in 4 chance of having
the disease. Cystic fibrosis occurs most frequently in Caucasians of northern European
descent, in whom the CF gene is most common — although people of other heritages
can get the disease, too.
People who have a close relative with CF are also more likely to carry the CF gene
— approximately 12 million Americans, or 1 in every 20 people living in
this country, is a CF carrier. And most of them don't know it. Parents can be tested
to see if they carry the CF gene, but because there are hundreds of specific CF gene
mutations (not all of which are known), genetic testing for CF won't detect everyone
who is carrying a CF gene.
Doctors can also perform tests during pregnancy so prospective parents can find
out more about the chances that their child will have CF. However, these tests also
won't always detect a CF gene.
What Happens When You Have CF?
Doctors diagnose most kids with CF by the time they are 3 years old, but if someone
has a milder form of the disease, it may not be diagnosed until that person reaches
the teen years. Babies are usually tested if they are born with an intestinal
blockage called meconium ileus, which is more common in CF infants.
Other symptoms include:
frequent lung infections or pneumonia
persistent cough with thick mucus
bulky, light-colored, foul-smelling bowel movements or diarrhea (because food
isn't being digested properly)
failure to gain weight, even though the child eats normal amounts
very salty sweat
poor height growth
nasal polyps (small growths of tissue inside the nose)
frequent sinus infections
People with CF get frequent lung infections that can damage their lungs over time
and require strong antibiotics along with stays in the hospital. They may have trouble
growing or gaining weight because of digestive problems.
Adults with CF may also develop other illnesses, such as diabetes (when blood sugar is too high) or osteoporosis (a weakening
of the bones).
The ends of the toes and fingers may become rounded and enlarged, a condition that's
What Do Doctors Do?
If doctors suspect that a person has CF, they will order a sweat test.
In this test, the doctor or technician uses a chemical and a very mild electrical
current to cause sweating on an area of skin, usually on a person's forearm (this
test doesn't hurt). The doctor or technician collects a large amount of sweat in a
pad and then analyzes it.
If the test results show a high level of chloride (a chemical in salt), there's
a possibility the person has CF. In some states in the United States, all newborns
are checked for CF with a blood test, although the blood test isn't as good at detecting
the disease as the sweat test.
Doctors and people with CF can do several things to slow the progression of the
disease and fight its complications. To loosen mucus, people with CF exercise regularly
and may use inhalers (like kids with asthma use) or nebulizers that
help deliver medication to the lungs.
Coughing helps people with CF clear the mucus from their lungs. They may also take
antibiotics to prevent or fight lung infections. Chest physical therapy may also be
an important part of the CF treatment routine. After lying down in a position that
helps drain mucus from the lungs, the person has a helper, such as a parent, gently
bang on his or her chest or back to loosen the mucus.
A newer device called a therapy vest shakes the chest, allowing teens to be more
independent by doing their therapy on their own.
For digestive problems, someone with CF can take enzymes by mouth to help digest
food and get nutrients
from it. A doctor may also prescribe vitamin supplements and a high-calorie diet.
Living With CF
Right now, there is no cure for CF. Even if symptoms are mild at first, they get
steadily worse over time.
But there is hope: 15 years ago, most children with CF would die before reaching
their teens. Now, with new treatments available, more than half live into their thirties,
and new research is leading to the possibility of a cure. Statistics now show that
nearly 40% of the people living with CF in the United States are 18 years or older.
Since researchers identified the gene that causes CF in 1989, they have tried to
replace abnormal CF genes with normal ones. Some are working on finding the right
method of delivering that normal gene into the cells of a person with CF. Other scientists
are trying to find new ways of fighting lung infections and different ways of moving
chloride in and out of cells, bypassing the defective CFTR protein. In some cases,
lung transplants have extended the lives of people with CF.
If someone you know has CF, you can be a supportive friend by learning about the
disease so you can help others understand what your friend is going through. Just
hanging out with your friend and taking part in the activities you enjoy doing together
can be a great help.
If you have CF, focus on staying as healthy as possible by following your doctor's
treatment instructions, taking your medications, eating right, and exercising. Meeting
other teens who have CF via chat rooms is fine, although personal contact between
two CF patients can present problems since it carries the risk of passing dangerous
bacteria to each other.
Your hospital's child life and CF specialists will have all kinds of ideas and
tips for coping with the disease and keeping your spirits up. Ask them to recommend
groups you might join, either online or locally. They can provide you with information
about clinical trials, legislative actions, handouts about CF, and even a college
or vocational school scholarship program.