Cystic fibrosis is an inherited genetic disorder. It is caused by a gene mutation that causes cells to secrete an abnormally thick and sticky mucus. The mucus interferes with the normal functions of the lungs and airways, and affects other organs of the body including those of the digestive system and the skin. It also makes the affected organs prone to infection.
Cystic fibrosis appears mainly during childhood and early adulthood. It is a serious medical condition that can lead to premature death. While it cannot be cured, it can be managed successfully with proper treatment.
A thick, viscous liquid that is secreted for lubrication and to form a protective lining over certain tissues.
Many organs and tissues of our body have glands that secrete mucus. This watery substance forms layers that keep the linings of our internal organs moist and also helps trap and remove harmful foreign substances and microbes.
In cystic fibrosis a gene called CFTR, which plays a vital role in mucus production, is faulty. The gene makes the CFTR protein, which is essential for balancing the salt concentration in the body's cells. When it does not work properly, the cells that produce the mucus do not secrete enough water, resulting in mucus that is dense, thick and sticky.
This type of mucus clogs up the lungs and makes it hard for them to operate. The mucus can also block tubes in the pancreas, which affects normal digestion. It also provides a rich breeding ground for bacteria, so infections are common.
Cystic fibrosis results in a build-up of thick mucus in organs such as the lungs and pancreas.
A thick, viscous liquid that is secreted for lubrication and to form a protective lining over certain tissues.
An organ located behind the stomach that secretes insulin and glucagon into the bloodstream and digestive enzymes into the intestines.
About 70,000 people have cystic fibrosis in the world today. [1] The condition is the most common hereditary disease for people of northern European descent and is uncommon amongst other types of populations.
Millions of people of northern European ancestry carry a single defective copy of the CFTR gene, without developing cystic fibrosis. The CFTR gene exists as two copies and in these individuals (known as carriers), their second copy is healthy. For an individual to develop cystic fibrosis, two copies of the defective CFTR gene are required. This can occur when two carriers, each with one defective CFTR gene, have a child who inherits two defective genes. The chance of this occurring is one-in-four.
Parents that carry a defective CFTR gene have a one-in-four chance of having a child with cystic fibrosis.
Cystic fibrosis foundation. Accessed 17 September 2014, from
Cystic fibrosis can appear in many forms. This is because the CFTR gene can have more than 1,500 mutations, each with a unique effect on the gene's function. As a result, cystic fibrosis varies between people; it can be mild to severe, and appear in different stages of life. In most people, the effects on the lungs are the most serious, but for some people the digestive system is the most affected.
The main signs and symptoms of cystic fibrosis occur in the respiratory and digestive systems.
The mucus blocks the pancreatic tubes, preventing the digestive enzymes from the pancreas from reaching the stomach and intestines. These enzymes are necessary for normal digestion. Without this function a range of the following digestion-related conditions can develop:
A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.
A thick, viscous liquid that is secreted for lubrication and to form a protective lining over certain tissues.
An organ located behind the stomach that secretes insulin and glucagon into the bloodstream and digestive enzymes into the intestines.
An abnormal enlargement of the tips of fingers, or toes, and a change in the angle where the nails emerge.
Breathing with a whistling or rattling sound in the chest.
The diagnosis of cystic fibrosis combines two approaches:
Almost all cases of cystic fibrosis are diagnosed shortly after birth through routine screening. However, some infants show only the milder signs of cystic fibrosis. These signs can be hard to detect early, so clinical testing may be needed.
Newborns and prospective parents can be checked for the presence of a mutated CFTR gene from a tissue sample. The test can also specify the type of the CFTR mutation present.
Genetic tests for cystic fibrosis include:
Couples planning a pregnancy, who have family histories of cystic fibrosis, may choose to check whether they are carriers of a mutated CFTR gene. This test is performed on a sample of saliva or blood.
If there is a reason to suspect that a fetus might have cystic fibrosis, a doctor can take a sample of the amniotic fluid, using amniocentesis, or the placenta, using chorionic villus sampling.
In many countries, screening of newborns for cystic fibrosis, and other genetic conditions after birth, is a routine procedure. A small blood sample is taken by pricking the baby's heel which then analyzed.
Clinical tests assess the impact of cystic fibrosis on the body. These tests can include:
This is the traditional clinical test for cystic fibrosis. A doctor will induce sweating on a small patch of skin with a weak and painless electrical current, which is then analyzed for the salt content.
A sweat test can be used to diagnose cystic fibrosis.
An X-ray of the chest can be used to check for lung inflammation and other typical signs of cystic fibrosis.
Numerous other tests can be performed depending on the regions of the body that are affected by cystic fibrosis. These can include blood tests, scans and procedures, such as bronchoscopy.
A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.
A scan that uses ionizing radiation beams to create an image of the body’s internal structures.
A test performed between 16 and 20 weeks into pregnancy to diagnose genetic abnormalities in the unborn baby, such as Down's syndrome. The test involves removing a sample of (amniotic) fluid around the unborn baby for analysis.
A test carried out usually between 10 and 12 weeks of pregnancy on a sample of placenta, to diagnose Down's syndrome or other genetic abnormalities in the unborn baby.
There is currently no cure for cystic fibrosis. However, recent developments in diagnosis and treatment of the disease mean that people with cystic fibrosis can now enjoy a greatly improved lifespan and quality of life.
Current treatment strategies focus mainly on reducing the production of mucus, preventing infections and managing the nutritional problems that result from having cystic fibrosis.
Treatments for cystic fibrosis include:
There are several therapy techniques that can help to physically clear the lungs and airways of the mucus build-up. This is done on a regular basis, usually once a day.
The treatment generally involves a carer or health professional thumping the chest area of the patient in a variety of ways and postures. Breathing exercises are also used, as well as devices that use vibration and air compression to help dislodge and clear mucus from the airways.
Nasal congestion can be cleared with the aid of inhalation, or a gentle flushing of the nasal passages with a salt rinse.
Exercise can help to reduce inflammation, encourage air flow and loosen mucus from the respiratory system. Exercise can also maintain healthy function of the joints and muscles of the chest and back, and can improve breathing.
Medication to treat respiratory problems in cystic fibrosis can be divided into five categories:
Lung transplantation can sometimes be recommended in cases of severe lung disease. However, this transplantation does not cure cystic fibrosis in other affected organs.
People with cystic fibrosis benefit from a carefully planned diet to help them cope with their impaired digestive system. The increased loss of salt from the body means it is important to keep a close eye on hydration and salt levels, especially during exercise.
Regular supplements of enzymes help to replace the body's own digestive enzymes, which cannot otherwise reach the intestines. These help to offset malnutrition and other symptoms associated with cystic fibrosis.
These are given to replace the nutrients that people with cystic fibrosis do not absorb from their diet. They include electrolyte and vitamin supplements.
In some cases of intestinal blockage, surgery may be needed.
A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.
A thick, viscous liquid that is secreted for lubrication and to form a protective lining over certain tissues.
The bodily parts comprising mainly the lungs and the airways. Its primary function is the intake and exchange of oxygen and carbon dioxide gases, respectively.
Ivacaftor. Medline Plus – U.S. National Library of Medicine. Accessed 22 June 2015, from
Problems with lungs are the main complications associated with cystic fibrosis, causing about 85% of deaths. [3] The onset of complications occurs over a period of time, as the repeated damage from mucus, inflammation and infections accumulates in the lungs. Some of the complications include:
Complications of the digestive system include:
As cystic fibrosis progresses over time, it can contribute to several other health problems. These can include:
A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterized by high blood sugar levels. Also known as diabetes mellitus.
A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.
A thick, viscous liquid that is secreted for lubrication and to form a protective lining over certain tissues.
An organ located behind the stomach that secretes insulin and glucagon into the bloodstream and digestive enzymes into the intestines.
Rishishwar L. Varghese N. Tyagi E. et al. (2012) Relating the disease mutation spectrum to the evolution of the cystic fibrosis transmembrane conductance regulator (CFTR). PloS One 7: e42336.
Barrio R. (2015) Management of endocrine disease: cystic fibrosis-related diabetes: novel pathogenic insights opening new therapeutic avenues. European Journal of Endocrinology 172: R131–R141.
Until recent times, people with cystic fibrosis were not expected to survive beyond their teenage years. Today, advances in treatment have allowed people with cystic fibrosis to live well into adulthood. The current average life expectancy of people with cystic fibrosis is 38 years.
People with cystic fibrosis can expect to lead a relatively normal life if they follow the nutritional, physical and medication routines described above. Their increased susceptibility to infection means they tend to spend more time in hospital, but they can still continue to study, work and enjoy social and romantic relationships.
Living with cystic fibrosis can sometimes be emotionally difficult. People with cystic fibrosis are encouraged to share any emotional issues they may have with family, friends and healthcare professionals. They are at increased risk of developing depression.
There are dedicated cystic fibrosis support groups, like the Cystic Fibrosis Foundation, who can provide resources, support and connect you with other people living with the condition.
Cystic fibrosis cannot be prevented. As a genetic disease, the only preventative measures are screening for the genetic defect, either before conception or before birth.