Cystic fibrosis (in German "Mukoviszidose"; CF) is a congenital metabolic disease in which a gene mutation causes the body to produce thick, sticky mucus. This mucus clogs the airways, the pancreas and other organs and leads to chronic infections and progressive organ damage.¹
Cystic fibrosis is the most common life-shortening hereditary disease in people of European descent. Thanks to modern therapies — in particular the CFTR modulators — life expectancy has improved dramatically in recent decades. Many of those affected today reach adulthood and lead a largely independent life.¹,²
Newborn screening since 2016
Since 2016, every newborn in Germany has been tested for cystic fibrosis as part of newborn screening — so the diagnosis is usually made before the first symptoms appear.
2. Causes
CFTR gene: cystic fibrosis is caused by mutations in the CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator). The CFTR protein works as a chloride channel in the cell surface and regulates the water and salt balance. In CF, this protein is defective or missing.¹
Autosomal recessive: both parents must be carriers of a CFTR mutation. If each parent is a carrier, every child has a probability of one in four of developing CF.
Mutations: there are over 2,000 known CFTR mutations. The most common is F508del. The type of mutation determines the severity and whether treatment with CFTR modulators is possible.
3. Symptoms
Lungs and airways
Chronic cough with thick, viscous sputum
Recurrent respiratory infections and pneumonia
Progressive impairment of lung function
Shortness of breath on exertion
Colonization with typical germs (e.g. Pseudomonas aeruginosa, Staphylococcus aureus)
Digestion and pancreas
Exocrine pancreatic insufficiency — the pancreas does not produce enough digestive enzymes; affects the large majority of those affected
Diabetes (CF-related diabetes, CFRD) — affects a relevant share of adults with CF
Liver disease — caused by thick mucus in the bile ducts
Infertility in men — usually due to absence or obstruction of the vas deferens (CBAVD)
Sinus infections — chronic
Salty sweat — often the first sign that parents notice
Osteoporosis — through vitamin D deficiency and nutritional problems
4. Diagnosis
Newborn screening: mandatory in Germany since 2016. Mostly detects CF before symptoms appear. A positive screening result has to be confirmed by further tests.¹
Sweat test: the gold standard of CF diagnostics. It measures the chloride concentration in sweat. Elevated values are diagnostic for CF.
Genetic test: identifies the specific CFTR mutations. Important for treatment planning — CFTR modulators only work with certain mutations.
Lung function test (spirometry): regularly from preschool age — FEV1 (forced expiratory volume in one second) is the most important parameter for monitoring lung function.
CFTR modulators are medications that act directly on the defective CFTR protein — they are the most important therapeutic innovation in cystic fibrosis of recent decades.¹,³
The currently most effective combination. Approved for those affected from the age of six with at least one F508del mutation (which applies to the large majority of people with CF in Germany). It can considerably improve lung function, body weight and quality of life. It has fundamentally changed the prognosis in CF.³
Older combinations — today largely replaced by Kaftrio, but still relevant for specific mutations.
Not suitable for all people with CF
CFTR modulators only work with certain mutations. Those affected with rare mutations for which no modulator is approved depend on symptomatic therapy. Research into further modulators and gene therapy is ongoing.
Practically important
Regular laboratory checks (liver values) are necessary while on CFTR modulators. Interactions with other medications — in particular azole antifungals, macrolide antibiotics and some statins — have to be taken into account. They are usually taken with a fat-containing meal (which improves absorption).
6. Treatment: symptomatic
Even with CFTR modulators, symptomatic therapy remains a central building block.¹
Inhalation therapy
Mucolytics (e.g. dornase alfa, hypertonic saline) loosen the thick mucus in the airways. Bronchodilators widen the airways. Inhalation therapy is usually needed daily and is time-consuming.
Chest physiotherapy
Special techniques for secretion drainage (autogenic drainage, PEP systems, the active cycle of breathing techniques). Usually daily. It is part of the core of CF therapy.¹
Antibiotics
For pulmonary infections — oral, inhaled or intravenous (with severe exacerbations). A first Pseudomonas colonization is usually eradicated aggressively.
Exercise and sport
Regular physical activity improves lung function, mucus mobilization and quality of life. It is expressly recommended.
Lung transplant
With end-stage lung disease, it can be the last treatment option. The decision is made individually at a specialized CF centre.
7. Nutrition and digestion
High in calories: people with CF usually have an increased energy requirement. A high-calorie diet is important to maintain weight and muscle mass.
Pancreatic enzyme replacement (PERT): capsules with digestive enzymes are taken with every fat-containing meal. The dose is adjusted individually. Without PERT, nutrients cannot be absorbed adequately.
Fat-soluble vitamins: supplementation of vitamins A, D, E and K is usually necessary, because these are not adequately absorbed due to the pancreatic insufficiency.
Salt intake: people with CF lose an above-average amount of salt through their sweat. Especially in heat, during sport or with a fever, an increased salt intake can be necessary.
CFRD: CF-related diabetes usually requires insulin therapy. Regular screening is recommended.
8. Everyday life with cystic fibrosis
Daily structure: inhalation, physiotherapy, taking medications, nutrition — the daily treatment effort is considerable and requires discipline and organization. Digital reminder systems can help.
CF centre: care should usually take place at a specialized CF centre — generally with check-up appointments every one to three months.
Hygiene and protection from cross-infection: people with CF have to observe certain hygiene measures, since they are susceptible to lung infections. Contact with other people with CF should be avoided because of the risk of cross-infection (no shared waiting rooms).
Transition: the move from paediatric to adult medicine is an important step. Specialized adult CF centres take over the care.
Mental health: the high treatment burden, the chronic disease and life planning can strain mental health. Psychological support should be offered regularly.
How brite helps you with cystic fibrosis
Kaftrio with a fat-containing meal, pancreatic enzymes with every meal, fat-soluble vitamins, inhalations, antibiotics in courses — the CF treatment plan is one of the densest there is. brite helps you keep track and not forget anything.
Medication reminder — Kaftrio (with a fat-containing meal), pancreatic enzymes with every meal, vitamins A/D/E/K, inhalations morning and evening, antibiotic courses: brite reminds you on time about every component. Set up a reminder
Interaction check — CFTR modulators have relevant interactions, especially with azole antifungals (e.g. fluconazole, itraconazole) and macrolide antibiotics (e.g. clarithromycin). Grapefruit juice also affects the levels. brite shows the critical combinations. Check now
Health history — document lung function (FEV1), weight, exacerbations, the antibiotics taken and treatment adherence over time. At your next appointment at the CF centre, be able to show the real course. Track your history
Digital medication plan — all your medications clearly laid out for the CF centre, pulmonology, your family doctor and the emergency department. In an emergency (e.g. an acute exacerbation), those treating you immediately see the complete treatment regimen. Go to medication plan
Medications that act directly on the defective CFTR protein and partly restore its function. The most effective combination is elexacaftor/tezacaftor/ivacaftor (Kaftrio). It can considerably improve lung function, weight and quality of life and has fundamentally changed the prognosis in CF.³
Not according to current knowledge. CFTR modulators treat the underlying cause at the protein level but cannot correct the gene mutation. Gene therapy approaches are in research. With modern therapy, however, many of those affected today reach a largely independent life into adulthood.¹
Autosomal recessive: both parents must be carriers of a CFTR mutation. Every child then has a probability of one in four of developing CF. Carriers themselves are usually healthy.
The gold standard of CF diagnostics. It measures the chloride concentration in sweat. People with CF have elevated chloride values in their sweat. The test is painless and can usually be carried out from infancy.
People with CF usually have an increased energy requirement due to the chronic inflammation, the increased work of breathing and the impaired absorption of nutrients with pancreatic insufficiency. An adequate calorie intake is important for weight, muscle mass and lung function.
Capsules with digestive enzymes (lipase, amylase, protease) that are taken with every fat-containing meal. They replace the missing enzymes of the pancreas and make nutrient absorption possible. The dose is adjusted individually.
To avoid cross-infections. Certain bacteria (especially Pseudomonas aeruginosa, Burkholderia cepacia) can be transmitted from one person with CF to another and cause severe lung infections. That is why separate waiting rooms and appointments are recommended at CF centres.
Life expectancy has improved dramatically in recent decades. With CFTR modulators, many of those affected today are expected to live considerably longer than earlier generations. Concrete figures are hard to give, as the modern therapies have only been available for a few years.
Mukoviszidose e. V. — Bundesverband Cystische Fibrose. Therapieempfehlungen basieren auf ECFS Standards of Care 2024 und nationalen Empfehlungen. muko.info
Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or treatment. Cystic fibrosis requires specialized care at a CF centre. CFTR modulators have relevant side effects and interactions and should be taken only under medical supervision. Last updated: April 2026.
