Cystic Fibrosis
Genetic Disorder That Causes Fatal Lung Problems

Birth Defect Guide


sweat test for babies
Cystic Fibrosis Sweat Test

Cystic Fibrosis

Contents

What Is Cystic Fibrosis?
What Causes It?
What Are The Symptoms?
What Does It Mean To Have Cystic Fibrosis?
How Is It Diagnosed?
How Is It Treated?
What Is The Long-Term Expectation?
Can It Be Prevented?
Genetic Testing Before Pregnancy



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Birth Defects
Respiratory System
What Is Cystic Fibrosis?

It is a deadly genetic disorder that is passed down through families. People with the disease have a defective gene which causes the body to produce unusually thick sticky mucus that clogs the lungs and pancreas and promotes bacterial infections. The average life expectancy for someone with cystic fibrosis (CF) today is late 30s. This is a considerable improvement since the 1950s when few children with CF even made it to elementary school age. Most children with CF are diagnosed by the age of 2 although a small minority is not diagnosed until 18 or older (usually because they have a milder form of the disease).

What Causes It?

CF is caused by a defective gene which is inherited from the parents. Millions of Americans carry the defective CF gene but they never develop symptoms. That is because - to have CF you must inherit 2 defective genes - one from each of your parents. Whites are more likely to carry defective genes (1 in 25) compared to Hispanics (1 in 45), African Americans (1 in 60) and Asians (1 in 150).

What Are The Symptoms?

The symptoms can vary from person to person, but include:
• Persistent coughing, sometimes producing phlegm.
• Shortness of breath or wheezing.
• Poor growth or weight gain in childhood despite eating lots.
• Salty tasting skin.
• Difficulties passing bowel movements, or greasy stools.

What Does It Mean To Have Cystic Fibrosis?

What It Does Mean: Living With Cystic Fibrosis

CF causes the body to make a thick sticky mucus that:
• Clogs the lungs and causes lung infections like pneumonia.
• Blocks the pancreas and stops the body breaking down and absorbing food.

What It Does Not Mean
CF does not cause learning problems or mental retardation. Nor does it mean that a person has to use a wheelchair (it is sometimes confused with cerebral palsy which is a totally different condition that affects muscle control). Children with CF go on to do all the things that other children do: they go to school, learn how to drive, attend college, have successful careers, get married and have children. As many new treatments are currently in trial stage, children born with CF today have a good chance of living longer and experiencing a fulfilled life.

How Is It Diagnosed?

Newborn Screening
All babies in the U.S. are screened for diseases within a few days of birth (see baby care after delivery). The idea is, the sooner a disease is diagnosed, the sooner it can be treated. New born screening (NBS) is carried out by a healthcare worker at the hospital. A few drops of blood from a heel prick are placed on a special card called a Guthrie card. This card is then mailed to a state laboratory for testing for certain conditions (one of which is CF). A positive result might mean your baby has a disease, but it is not certain. Further diagnostic tests will be necessary.

Sweat Test
If your baby tests positive with a NBS, a sweat test is ordered. An odorless chemical is placed on the skin of the arm or leg and an electrode is attached to the spot. A weak electric current is passed through the electrode to cause sweating. The sweat is collected and sent to a laboratory for testing. People with CF have particularly salty skin.

How Is It Treated?

Early diagnosis and treatment of CF can considerably improve both survival and quality of life. Continual follow-up and monitoring is very important. Ideally patients should be cared for at specialty CF clinics. Antibiotics are taken to treat lung infections, and other therapies (such as TheraPEP device, manual chest percussion, Percussion Vest and A-capella) can help thin mucus to make coughing it up easier. The flu vaccine and pneumococcal polysaccharide vaccine (PPV) will be given every year. If lung disease worsens, oxygen therapy may be required. Nutritional and bowel problems are treated with a special diet (high in protein and calories), vitamin supplements and pancreatic enzymes.

What Is The Long-Term Expectation? (Prognosis)

Lung disease eventually incapacitates patients. Death is usually caused by lung complications. The average life span of CF people who live to adulthood is 37 years. Other complications include:
• Coughing up blood.
Diabetes.
Infertility in men.
• Liver failure.
• Malnutrition.
• Heart failure (right sided called cor pulmonale).
• Recurrent pneumonia.
• Sinusitis and nasal polyps.

Can It Be Prevented?

No, there is no way to prevent CF. Screening for CF in those with a family history of the disease may detect the CF gene in 60 to 90 percent of cases, depending on which test is used.

Genetic Testing Before Pregnancy

New genetic tests are available that allow couples at risk to see if one or both are carriers of the CF gene before conception. Although there are different types of tests, all involve taking a blood sample so that chromosomes can be analyzed. A genetic counselor will talk parents through the process. If both parents are carriers, the risk of the child developing CF is 1 in 4. The tests can identify up to 90 percent of carriers, but there are still a portion of carriers who will not be identified (10 percent). This means if one parent is a known carrier, there is a very small chance the other parent is too and that the offspring will be affected. Should a pregnancy occur, amniocentesis or chorionic villus sampling can screen the baby for CF and other conditions like Down syndrome. High risk couples who would consider an abortion may opt for CVS, even though it has a slightly higher risk of miscarriage than an amniocentesis. This is because the CVS can be performed sooner (as early as 10 to 13 weeks) when a termination is somewhat easier. Particularly high risk couples may consider IVF and pre-implantation genetic diagnosis (PGD). A single cell is extracted from the embryo and tested for signs of CF before it is implanted in the mother.

Related Articles
How important is genetic screening for IVF babies?

Related Articles on Genetic Disorders

For more advice, see the following:

Genetic Testing: Overview of tests and disorders.
Postpartum Period: What to expect after having a baby.

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