Cystic fibrosis

The rare metabolic disorder cystic fibrosis is hereditary and has no cure. Too much thick mucus accumulates in the lungs, causing a chronic cough and frequent infections. Thanks to ever-better treatments, patients’ quality of life and life expectancy are improving.

At a glance

  • Cystic fibrosis is a rare, hereditary metabolic disorder.
  • The initial symptoms usually appear in adolescence and adulthood.
  • The disorder often affects organs such as the lungs, pancreas and intestines.
  • Screening tests for newborns now make it possible to detect cystic fibrosis at an early stage.
  • There is no cure for cystic fibrosis but the accompanying and secondary conditions can be effectively treated.
  • The average life expectancy of people with cystic fibrosis is about 40 years. Thanks to good medical care, this is continuing to rise.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Man lying on a sofa. He is attached to a ventilator via a mask. There are various forms of medication on the table next to him.

What is cystic fibrosis?

Cystic fibrosis – also known as mucoviscidosis – is a non-curable hereditary metabolic disorder that can affect various organ systems, such as the airways, pancreas and intestines.

Changes to the genetic material disrupt the salt-water balance in certain cells. This results in the formation of thick mucus, which can cause chronic coughing if affecting the lungs.

Newborn screening can be used to diagnose and treat cystic fibrosis at an early stage. The average life expectancy of people with cystic fibrosis has risen significantly and is currently 40 years.

In Germany, about one in 4,500 children is born with cystic fibrosis every year.

What are the symptoms of cystic fibrosis?

Most children with cystic fibrosis do not present any symptoms at birth. One exception to this is meconium ileus: a bowel blockage due to thick stool that is experienced by about 20 percent of newborns with cystic fibrosis.

In most cases, the first symptoms usually occur in adolescence and adulthood. These can vary in severity. Typical symptoms include:

  • a chronic cough that lasts for at least 3 months, sometimes with wheezing, a shortness of breath and sputum
  • persistent airway infections
  • chronic inflammation of the nasal mucosa and sinuses
  • fingertip swelling (“clubbed fingers”)
  • “salty skin” due to chloride in the sweat
Initial symptoms of cystic fibrosis usually appear during adolescence and adulthood.

Many people with cystic fibrosis also have a congenital pancreatic weakness. This means that the pancreas does not produce enough digestive juices, resulting in digestive issues. This later results in impaired insulin production, which can develop into type 3 diabetes.

The indications of a pancreatic weakness include:

  • growth disorders in children
  • unexplained loss of weight in children, adolescents and adults
  • fatty stools (steatorrhea): foul-smelling, oily and bulky stools

What causes cystic fibrosis?

Cystic fibrosis is caused by a modified (mutated) gene that provides a blueprint for an important protein in the body. Known by the abbreviation CFTR, this gene regulates the salt-water balance of the mucosal gland cells – for example in the pancreas, the bronchi and the small intestine.

If the regulator is defective, the mucus is very thick. In the bronchi, this cannot be coughed up, impairs breathing and can cause chronic coughing. It is also possible for bacteria to settle in the mucus and cause repeated airway infections.

Viscous digestive juices damage the pancreas, reduce the intestinal absorption of important nutrients for the body and increase the risk of people becoming malnourished and underweight.

What is the probability of inheriting cystic fibrosis?

Cystic fibrosis results from a change (mutation) to the CFTR gene. This gene exists twice, whereby the term “copies” is used. Cystic fibrosis only develops if the mutation exists in both gene copies.

People with only one mutated CFTR copy will not suffer from the disease themselves but can pass on the mutation. If a mother and father each have a mutated copy, they can pass this on to their child. There is then a 25 percent probability of the child having cystic fibrosis. If one parent has cystic fibrosis and the other is a carrier – which is very rare – the probability increases to 50 percent.

How does cystic fibrosis progress?

The way in which cystic fibrosis develops can differ greatly and is unpredictable. Respiratory system disorders and digestive system disorders are particularly common. Fertility problems are also possible.

Respiratory system disorders

If the thick mucus collects in the airways – and especially in the lungs – a chronic cough can develop. In adults with cystic fibrosis in particular, it is also very common for this to result in sinusitis (inflammation of the sinuses) and mucosal growths in the nose or sinuses (nasal polyps).

Metabolic disorders

Some people with cystic fibrosis have a pancreatic weakness. This results in the body not using food properly and developing vitamin and mineral deficiencies. Children grow slower and do not develop properly. Some also reach puberty later.

Diabetes can also develop over the years. However, diabetes is rare in children below the age of 10. A further consequence can be a painful bowel blockage.

The bones of people with cystic fibrosis often contain too few minerals. Depending on their age, this greatly increases the prevalence of bone fractures and deformations as well as bone atrophy (osteoporosis).

Fertility disorders

Over 95 percent of men with cystic fibrosis are infertile as the spermatic duct does not develop properly in most of them. However, they usually still produce sperm and can therefore still become fathers with the aid of artificial fertilization. Women with cystic fibrosis can fall pregnant naturally, although this is somewhat harder than for women without cystic fibrosis. This is primarily due to the thick cervical mucus.

Important: Special advice is available for people with cystic fibrosis who want to have children.

Other secondary conditions

Some children with cystic fibrosis develop anemia. Up to a third develop chronic liver disease.

What screening options are available for cystic fibrosis?

Since 2016, all new-born babies in Germany have been tested for cystic fibrosis. The doctor takes a small drop of blood 36 to 72 hours after birth and sends it for laboratory testing.

Since 2016, all new-born babies in Germany have been tested for cystic fibrosis.

Certain proteins are measured in the blood and a targeted check is made for mutations in the CFTR gene in order to obtain indications of cystic fibrosis.

How reliable is the blood test screening?

At present, only one in four to five children who test positive actually have cystic fibrosis. That means that the blood test delivers a false positive for most children. A positive result is therefore confirmed or discredited through further diagnostic methods as soon as possible.

How is cystic fibrosis diagnosed?

In addition to the blood test result, a detailed medical consultation is also a prime factor. Doctors will ask, for example, whether family members have cystic fibrosis. As cystic fibrosis is hereditary, a family history provides important indications of a possible condition.

If the baby is suspected to have cystic fibrosis based on the family history or screening test results, the doctors perform what is known as a sweat test. The skin is stimulated to produce a high level of sweat. The sweat is collected and the chloride content is measured. Results above a certain threshold are an indication of cystic fibrosis.

The sweat test results are subsequently confirmed by genetic tests. If these results are still not clear, further tests also follow.

How can cystic fibrosis be treated?

There is no cure for cystic fibrosis but consistent long-term treatment can alleviate the symptoms. Nowadays, the accompanying and secondary conditions can also be effectively treated.

Specialist outpatient clinics and centers guarantee treatment and care that is tailored to the individual. They also offer psychological support and counseling to people with cystic fibrosis and their relatives.

Important: The sooner cystic fibrosis is diagnosed, the quicker the necessary treatment forms can be initiated. This improves the child’s physical development and positively affects the outlook of the disorder. As a result, newborns have been routinely tested for cystic fibrosis since 2016.

Drug treatment

Cystic fibrosis is often treated with several drugs at the same time. These include:

  • expectorants that are inhaled wet or dry
  • drugs to combat infections and inflammation of the airways, such as antibiotics and anti-inflammatory corticosteroids
  • so-called CFTR-modulating drugs like ivacaftor, which aim to regulate the impaired water-salt balance of the mucosal cells


Daily breathing exercises can loosen thick mucus and make it easier to breathe. The exercises are initially performed under the guidance of a physiotherapist and then independently at home.

Specially trained physiotherapists and relatives who have received professional guidance can also use chest treatments to loosen the mucus in the airways, making it easier to cough up.

Further treatment options

People with cystic fibrosis must be particularly careful to get enough nutrients. Dietary supplements may help to prevent deficiencies (but should only be taken following consultation with a doctor).

In the event of a severe disorder with permanent damage to the lung tissue, a lung transplant can prolong life.

Accompanying measures

Regular routine examinations are equally important. This enables doctors to identify and treat any changes – such as a deterioration of lung-related results – at an early stage. The same applies to accompanying and secondary conditions.

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen – IQWiG).

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