Cystic fibrosis (CF) is an inherited disorder that creates breathing and digestive problems by clogging organs in the body with a thick, sticky mucus.
- CF is the most common life-threatening inherited disorder in New Zealand. Approximately 1 in 25 people carry the CF gene.
- It affects the mucus and sweat glands causing mucus to be thick and sticky. This can block the tiny tubes in the lungs, intestine, liver and pancreas causing breathing problems, repeated lung infections and problems with digestion.
- It does not affect everyone equally and symptoms vary from mild to severe.
- Most babies in New Zealand who have cystic fibrosis are diagnosed at birth. Occasionally an adult can be diagnosed later in life but this is uncommon.
- CF is a long-term condition that has a huge impact on a person’s life. However, with appropriate treatment, care and support, most people with CF still manage to live a normal life.
What causes cystic fibrosis?
Cystic fibrosis is caused by a problem or mutation in one of our genes.
- The specific mutation for CF is found on chromosome 7 and is known as the ‘cystic fibrosis transmembrane conductance regulator’ (CFTR) gene. The CFTR gene helps move salt in and out of your cells. In CF, the movement of salt doesn’t happen properly.
- At least 1,700 mutations of the CFTR gene have been found.
- Different mutations can influence how you are affected, but knowing your mutation can’t predict how severe your symptoms will be.
Who is at risk?
One in 25 people in New Zealand carry the CF gene. Often people do not know they carry the CF gene, as it causes no symptoms.
To be born with CF, a child needs to inherit two faulty genes: one from their mother and one from their father.
If both parents carry the CFTR gene, with each pregnancy there is a:
- 1 in 4 chance that your child will have CF
- 2 in 4 chance that your child will be a carrier of the CF gene
- 1 in 4 chance that your child will not have CF and will not be a carrier.
Image source: Genetics of cystic fibrosis (pdf) a layperson’s guide Cystic Fibrosis New Zealand.
CF affects 1 in 3,500 newborns. Among different ethnic groups:
- CF is the most common inherited disease in European or Caucasian populations.
- CF is less common in African, Maori and Pacific populations.
What are the symptoms of cystic fibrosis?
Symptoms of cystic fibrosis vary and depend upon age and disease severity.
In babies, symptoms can include:
- delayed growth or failure to gain weight normally
- no bowel movements in first 24 to 48 hours of life
- salty-tasting skin.
In children and adults symptoms may include:
- weight loss or poor weight gain or growth
- severe constipation and abdominal pain
- nausea and loss of appetite
- increased gas or bloating or a belly that appears swollen (distended)
- stools (poo) that are pale or clay coloured, foul smelling, have mucus or that float
- infertility (in men)
- coughing and increased mucus in the chest
- recurrent chest infections or pneumonia
- sinus pain and infections (50% of people with CF have nasal polyps).
What complications can occur with cystic fibrosis?
Complications from cystic fibrosis often affect the lungs and digestive system.
In the lungs CF can cause:
- chronic cough
- shortness of breath
- repeated chest infections
In the digestive system CF can block or reduce the release of enzymes from the pancreas that helps to break down food. This is called pancreatic insufficiency, which affects 85% of people with CF. This leads to poor weight gain and malnutrition.
Other complications include:
- nasal polyps, which affect 50% of people with CF
- liver disease, which usually affects up to 30% of people with CF by adulthood
- CF-related diabetes, which is usually present in 2% of children, 19% of adolescents and 40-50% of adults with CF
- progressive respiratory failure.
How is cystic fibrosis diagnosed?
The diagnosis of cystic fibrosis is made through a range of tests.
Guthrie heel prick
Most babies with CF are diagnosed through a screening test done shortly after birth. This test, called the Guthrie heel prick, checks for many genetic disorders. If a heel prick test is abnormal your child will be referred for further tests.
The sweat test is another way of making a diagnosis of cystic fibrosis. Here, an abnormally high level of salt is found in a child or adult's sweat.
Chorionic villus sampling
In women who are pregnant, a special test known as chorionic villus sampling may be performed. A small amount of fluid is removed from the womb and is analysed for the presence of the CFTR gene.
Genetic testing through a blood test can also be offered to family members, potential partners or to help detect carriers of the CFTR gene. Genetic testing is also available to people without a family history of CF. It is not publicly funded and the finding should be used together with genetic counselling.
X-ray and sputum analysis
Patients who develop chest infections may require an x-ray and analysis of the sputum to detect the presence of any bacteria.
What is the treatment for cystic fibrosis?
Cystic fibrosis is a life-long condition for which there is currently no cure. Treatments and life expectancy have dramatically improved over recent years. New drugs are being researched and developed that specifically target the genetic mutation, meaning they treat the actual cause of CF and not just the symptoms.
The goals of CF treatment include:
- preventing and controlling lung infections
- clearing the thick, sticky mucus from the lungs
- reducing inflammation and improving lung function
- preventing or treating blockages in the intestines
- ensuring enough nutrition and preventing dehydration (a lack of fluid in the body).
Treatment options for CF include:
- inhaled enzymes (called Pulmozyme)
- insulin to manage diabetes
- inhalers to open up the airways
- steroids to help reduce swelling within the airways
- physiotherapy and postural drainage of the chest.
- diet tailored to your needs – often a special diet that is high protein and calories is needed
- pancreatic enzymes to help absorb fats and protein
- vitamin supplements, especially vitamins A, D, E and K
- nasal steroids for, or surgical removal of, nasal polyps.
Treatment can be complex and is best is coordinated by a specialist team working alongside the patient, their family and their doctor.
Can cystic fibrosis be prevented?
Unfortunately, cystic fibrosis cannot be prevented. If the parents are both carriers of the gene, then there is a 1 in 4 chance that the child will get the condition. However, steps can be taken to ensure that the child leads a healthy and normal life. This can include:
- chest physiotherapy and postural drainage of the lungs
- constant cycles of antibiotics to help prevent infections from occurring
- immunisations to help reduce the chance of developing new infections
- maintaining good nutrition and an ideal body weight to help fight off infections.