General Condition Information
There are no other recognized names for this condition.
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- It is estimated that at least a thousand babies are born with this condition each year in the United States.
- It is less common in African American and Asian American babies.
- Visit GeneReviews to learn more about how often this condition occurs.
What is Cystic fibrosis
Cystic fibrosis is an inherited (genetic) condition that causes thick and sticky mucus to build up in the body. The thick mucus can lead to fluid-filled sacs (cysts) and scar tissue (fibrosis) in organs.
Cystic fibrosis results when a protein that controls how salt flows in and out of cells does not work properly. When salt doesn’t go where it needs to, levels of water in certain parts of the body are too high in some places and too low in others. When mucus does not have enough water, it turns from thin and slippery to thick and sticky.
This thick mucus causes problems with the respiratory system, the digestive system, the reproductive system, and other parts of the body.
Thick mucus in the lungs can block the airways, making it difficult to breathe, and leading to lung infections. When the immune system responds to infections in people with cystic fibrosis, waste products from the germ-killing cells get stuck in the mucus. This waste damages the lungs.
Thickened mucus can affect digestion and make it hard to get nutrients from food. Lack of nutrients can prevent normal growth and development.
If not treated, the combination of the salt imbalance and thick mucus leads to the signs and symptoms of the condition.
Newborn Screening and Follow-Up
Newborn screening for cystic fibrosis is done using a small amount of blood collected from your baby’s heel. To learn more about this process, visit the Blood Spot Screening page.
During screening, a special machine measures how much of a certain substance (called immunoreactive trypsinogen or IRT) is in your baby’s blood. IRT is made in the pancreas and is increased in newborns with cystic fibrosis.
In most cases, if a baby’s IRT is elevated, a second test will also be done on the newborn screening sample. This second test looks for changes in the gene that causes CF (called CFTR). Babies with high levels of IRT and at least one change in the CFTR gene may have CF.
Newborn screening for cystic fibrosis is important even if a mother already received screening during pregnancy. In some cases, newborn screening for cystic fibrosis may show different results than prenatal testing. It is important to always follow-up with an out-of-range newborn screening result– even if testing during pregnancy was normal.
If your baby’s blood spot screening result for cystic fibrosis is out-of-range, your baby’s health care provider will contact you. Together, you will discuss next steps and follow-up plans.
If your baby’s screening results show high IRT levels and only one change in the CFTR gene, this result does not mean that your baby definitely has CF. It does mean that your baby needs more follow-up testing.
If your baby’s screening results show high IRT levels and two or more changes in the CFTR gene, it is likely that your baby has CF and needs more follow-up testing.
To learn more about screening results, visit the Blood Spot Screening Results page.
Your baby may need the following tests after an out-of-range screening result:
- Sweat testing to check for the presence of increased chloride (salt)
- Blood and/or urine tests
- Genetic testing using a blood sample
You should complete any recommended follow-up testing as soon as possible. Babies with this condition can have serious health problems if they are not diagnosed and treated quickly.
False-positive newborn screening results for this condition can happen in the following cases:
- Babies who are cystic fibrosis carriers
- Babies whose screening samples were collected before they were 24 hours old
- Babies who are very sick with conditions other than cystic fibrosis
False-negative newborn screening results for this condition can also happen. In some cases, babies with cystic fibrosis have normal levels of IRT and do not get picked up by screening.
Newborn screening helps babies lead healthier lives. If your baby has an out-of-range result, follow up with your health care provider quickly. It is important to follow their instructions. Your baby may need to get treatment right away, even if they are not showing signs or symptoms. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps. Careful monitoring and early treatment will help your baby stay as healthy as possible.
Signs of cystic fibrosis often appear shortly after birth, but some may not appear right away.
Signs may include the following:
- Salty sweat
- Thick mucus
- Frequent coughing or wheezing
- Diarrhea, greasy, or pale-colored stools
- Poor growth
- Weight loss
The condition is caused by a change in the CFTR gene. This gene gives your body instructions for making a channel made of protein that moves salt (chloride ions) in and out of cells. Salt controls the amount of water in and around cells.
Without a working CFTR gene, this channel cannot keep a proper salt balance. An imbalance of salt means there is not enough water in mucus to keep it thin, so it becomes thick and sticky. The thick, sticky mucus blocks airways and ducts, causing problems with multiple systems in your baby’s body.
- Cystic fibrosis is an autosomal recessive condition. Babies inherit the condition when each parent passes down a nonworking CFTR gene to their baby. Only babies with two nonworking CFTR genes—one from the mom and one from the dad—have this condition.
- People with one working copy and one nonworking copy of the CFTR gene are called carriers.
- Carriers do not have or develop the condition. However, they may pass down a nonworking copy of the gene to their children.
- If two parents are carriers of a nonworking copy of the CFTR gene, they have a 1 in 4 chance of having a child with cystic fibrosis.
- Carriers for cystic fibrosis often do not know they are carriers before having a child with the condition. In most cases, families have no history of the condition until the birth of a child with cystic fibrosis.
- Parents who already have a child with cystic fibrosis still have a 1 in 4 chance of having another child with cystic fibrosis. This 1 in 4 chance stays the same for all future children.
- Genetic counselors and medical geneticists can help families learn about this condition and the chance of having children with it. Visit the National Society of Genetic Counselors to find a genetic counselor and the American College of Medical Genetics and Genomics to find a medical geneticist.
Treatment and Management
It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to prevent the health problems caused by this condition.
Treatments may include the following:
- Airway clearance therapy (ACT)
- Dietary treatments
- High-calorie diet
- Pancreatic enzymes
- Vitamin supplements
- Medications to:
- Fight infection (antibiotics)
- Reduce swelling (anti-inflammatories)
- Thin mucus (mucus thinners)
- Widen the airways (bronchodilators)
- Personalized treatments that target specific CFTR gene changes
Children who receive early and ongoing treatment for cystic fibrosis can have healthy growth and development. Treatment is very important for managing cystic fibrosis symptoms and delaying damage.