What is cystic fibrosis?
Cystic fibrosis (CF) is a genetic disorder that affects the lungs and digestive system by making fluids and mucus in these organs thick and sticky. It is an inherited disease.
CF disrupts the normal function of epithelial cells –cells that line passageways inside the lungs, liver, pancreas, sweat glands, digestive and reproductive systems. The faulty CF gene directs the body to produce a defective form of a protein, called Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). Cells with defective CFTR can't regulate the way salt passes across cell membranes. This disrupts the essential balance of salt and water needed to maintain a normal, thin coating of fluid and mucus along these linings inside the lungs, pancreas and other organs.
Normally, mucus in the lungs traps germs, which are then cleared out of the lungs through coughing. But in CF, the thick, sticky mucus and trapped germs remain in the lungs, which can cause lung infections.
In the pancreas, thick mucus blocks the passages that would normally carry enzymes to the intestines to digest foods. When this happens, the body can't process or absorb nutrients properly, especially fats. Kids with CF have problems gaining weight, even with a normal diet and a good appetite.
Now, thanks to high-tech medical advances in drug therapy and genetics, children born with CF can look forward to longer and more comfortable lives. Since the 1980s, research into all aspects of CF has helped doctors to understand the disorder better and to develop new therapies that help kids live well into adulthood. There have been very promising recent breakthroughs particularly in the area of CFTR protein rescue therapy.
What causes cystic fibrosis?
Humans have 23 pairs of chromosomes made of the inherited genetic chemical deoxyribonucleic acid (DNA). The CF gene is found on chromosome number 7. It takes two copies of a CF gene –one inherited from each parent– for a child to show symptoms of CF.
People born with only one CF gene (inherited from only one parent) are CF carriers. CF carriers do not show CF symptoms themselves, but can pass the CF gene to their children. Scientists estimate that about 12 million Americans are currently CF carriers. If two CF carriers have a child, there is a 1 in 4 chance that the child will have CF.
Who gets cystic fibrosis?
More than 1,400 different genetic mutations of the CF gene can lead to cystic fibrosis, although some mutations cause milder symptoms than others. The most common mutation in the CF gene is called F508del; around 70% of people with CF have this genetic mutation. CF gene mutations can be detected by genetic testing from blood samples.
Of all ethnic groups, Caucasians have the highest inherited risk for CF, and Asian Americans have the lowest. In the United States today, about 1 of every 3,600 Caucasian children and 1 of every 9,000 Hispanic children are born with CF. This compares with 1 of every 17,000 African Americans and only 1 of every 90,000 Asian Americans.
Although the chances of inherited risk may vary, CF has been identified in every geographic area of the world, among every ethnic population. CF affects more than 30,000 people in the United States.
Helpful cystic fibrosis resources
What are the signs and symptoms of cystic fibrosis?
The most common symptoms of CF among infants and children include:
- Lack of weight gain/"failure to thrive"
- Oily or bulky stool
- Excessive intestinal gas
- Abnormally swollen belly
- Abdominal pain or discomfort
- Salt crystals or salty taste on skin
- Nasal congestion
- Sinus problems
- Asthma-like symptoms
- Chronic cough that produces thick, discolored mucus
- Repeated lung infections or pneumonias
- Shortness of breath, even while resting
A few kids with CF begin having symptoms at birth. Some are born with a condition called meconium ileus. Although all newborns have meconium, (the thick, dark, putty-like substance that is a baby's first stool) in CF, the meconium can be too thick and sticky to pass and can completely block the intestines.
What tests are used to diagnose cystic fibrosis?
CF is most commonly diagnosed as part of newborn screening. This screening test occurs shortly after birth when a small amount of blood is taken to check for many conditions. A positive screen indicates the baby might have a health condition and that further testing should be done. Testing for CF is now included in the newborn screening protocol for all infants born in the U.S.
A positive (abnormal) newborn screen does not necessarily mean the baby has CF. A different test, called a diagnostic test, is needed to find out if the child has CF.
The two most definitive tests for diagnosing CF are a sweat test and genetic testing for CF-causing gene mutations. In the sweat test, a small, non-painful, electric current is used to carry the chemical pilocarpine into the skin of the forearm. This stimulates sweat glands in the area to produce sweat which is collected in a small tube and the salt (chloride) content is then tested. A sweat chloride concentration greater than 60 mmol/L is diagnostic of CF; chloride concentrations between 30-60 mmol/L are intermediate, and may indicate a milder form of CF. A diagnosis can also be made by identifying two CF mutations on genetic testing.
Several other tests are standard parts of routine care used to care for a child with CF:
- Chest X-rays or chest CT scans
- Blood tests to evaluate nutritional status
- Bacterial studies to test for Pseudomonas aeruginosa, Staphylococcus aureus or Haemophilus influenza bacteria in the lungs (these bacteria are common in CF but may not affect otherwise healthy people)
- Pulmonary function tests (PFTs) to measure the effects of CF on breathing. PFTs are done as soon as the child is old enough to be able to cooperate in the testing procedure; infant PFTs are currently being studied.
Because genetic screening for CF is available during pregnancy, parents can now learn whether their unborn children may have the condition. But even when genetic tests confirm CF, there's still no way to predict whether a child's CF symptoms will be severe or mild. Genetic testing also can be done on a child after birth, and can be performed on parents, siblings and other relatives who are considering having a family.
How do providers at Children's Hospital Colorado make a diagnosis?
At Children's Colorado, a diagnosis of CF is generally confirmed by finding elevated sweat chloride (greater than 60 mmol/L) and/or two CF-causing mutations through genetic testing. Sometimes children with sweat chloride results between 30 and 60 mmol/L have a more mild form of CF or a related, milder condition called Cystic Fibrosis Related Metabolic Syndrome or CRMS. Your doctor can help determine whether your child has CF or a related condition.
Doctors are diagnosing CF earlier and earlier, usually in infancy. However, about 15% of those with CF are diagnosed later in life, even into adulthood.
How is cystic fibrosis treated?
The main treatment strategies for people with CF are airway clearance, prevention and treatment of lung infections, and nutritional therapy.
The daily care program varies from child to child, but usually includes airway clearance treatments with nebulized medications that are mixed with air and then inhaled to help loosen and clear mucus from the lungs. Children may need frequent oral or inhaled antibiotics to treat lung infections.
Children with CF need a high-calorie, high-fat and high-protein diet. They often take oral pancreatic enzymes to help them digest food. They also need vitamin supplements (particularly fat-soluble vitamins A, D, E and K) and extra salt.
The CF Foundation recommends that all people with CF be followed in an accredited CF care center with regular visits at least every three months, and more often before age 1.
A new treatment for CF, which was approved by the FDA in 2012, is called Kalydeco™. This oral medication helps the abnormal CF protein (CFTR) to work better, and dramatically improves lung function and weight gain in people with CF. It is the first drug to treat the underlying problem in CF, rather than the symptoms. Unfortunately, because of the way it helps the protein to work, Kalydeco™ only benefits 4% of people with CF, those who have the G551D CF mutation. However, there are other drugs currently in clinical trials that may help many more people with CF, including those with the most common ΔF508 mutation.
Why choose Children's Hospital Colorado for your child's cystic fibrosis?
Children's Colorado is the site of one of the premiere cystic fibrosis (CF) clinical care and research centers in the country. The Mike McMorris Cystic Fibrosis Research and Care Center at Children's Colorado delivers state-of-the-art care to people with CF, provides education for healthcare professionals and families with CF and advances the field through clinical research.
Our center, established in 1990 and accredited by the National Cystic Fibrosis Foundation, is the largest CF clinical care center in the United States. Our pediatric program cares for more than 400 children and adolescents with CF throughout the Rocky Mountain region, and approximately 300 people with CF are seen at the adult program based at National Jewish Health. Our program has outreach clinics in Colorado Springs and oversees an affiliate CF center in Montana. We also serve as a national referral center because of our experience and advanced diagnostic capabilities.
Our program works to be patient-centered in many ways, including:
- We have established a CF Family Advisory Council, made up of our patients' parents and clinical staff, who work as partners with the CF clinical care team to ensure excellence in the development and delivery of medical care for those with CF and their families in the Rocky Mountain region.
- Our multidisciplinary CF care team includes board-certified pediatric pulmonologists and gastroenterologists, pediatric endocrinologists, CF clinical nurse specialists, registered dietitians, social workers respiratory therapists and research coordinators, as well as administrative support staff.
- Our clinics see children with CF five days a week, Monday through Friday.
- We offer comprehensive inpatient and outpatient multidisciplinary medical care.
- Our program consistently ranks as one of the top performing CF centers in the country based on lung function data in our children and adolescents.
- We work to continually improve care at our CF center through quality improvement initiatives and educational programs for health care providers and families.
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Children's Colorado in the news
Colorado Public Radio
noviembre 6, 2019
The newly approved triple-combo drug, Trikafta, has the potential to help 90% of people living with CF and add years to life expectancy.