Cystic fibrosis (CF) is a congenital metabolic disorder in which a gene mutation causes the body to produce thick, sticky mucus. This mucus blocks the airways, the pancreas and other organs and leads to chronic infections and progressive organ damage.¹
CF is the most common life-shortening inherited disease in people of European descent. Thanks to modern therapies — particularly CFTR modulators — life expectancy has improved dramatically over recent decades. Many affected people now reach adulthood and lead largely independent lives.¹,²
Newborn screening
In many countries — including the UK and Germany — every newborn is now screened for cystic fibrosis as part of national newborn screening programmes. The diagnosis is therefore typically made before symptoms appear.
2. Causes
CFTR gene: CF is caused by mutations in the CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator). The CFTR protein functions as a chloride channel at the cell surface and regulates 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 both parents are carriers, each child has a one in four chance of having CF.
Mutations: there are over 2,000 known CFTR mutations. The most common is F508del. The type of mutation determines disease severity and whether treatment with CFTR modulators is possible.
3. Symptoms
Lungs and airways
Chronic cough with thick sputum
Recurrent airway infections and pneumonia
Progressive impairment of lung function
Shortness of breath on exertion
Colonisation with typical organisms (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 people with CF
Failure to thrive in children — despite adequate food intake
Abdominal pain, bloating
Other organ involvement
Diabetes (CF-related diabetes, CFRD) — affects a relevant proportion of adults with CF
Liver disease — through thick mucus in the bile ducts
Male infertility — usually due to absence or obstruction of the vas deferens (CBAVD)
Chronic sinus infections
Salty sweat — often the first sign parents notice
Osteoporosis — through vitamin D deficiency and nutritional issues
4. Diagnosis
Newborn screening: in many countries part of routine national screening. Detects CF typically before symptoms appear. A positive screen must be confirmed by further tests.¹
Sweat test: the gold standard of CF diagnosis. 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 for 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.
5. Treatment: CFTR modulators
CFTR modulators are medications that act directly on the defective CFTR protein — they are the most important therapeutic innovation in CF in recent decades.¹,³
The currently most effective combination. Approved for people from age six with at least one F508del mutation (this covers the large majority of people with CF). Can substantially improve lung function, body weight and quality of life. Has fundamentally changed the prognosis in CF.³
Older combinations — now largely superseded by Kaftrio, but still relevant for specific mutations.
Not suitable for everyone with CF
CFTR modulators only work for certain mutations. People with rare mutations for which no modulator is approved still rely on symptomatic therapy. Research into further modulators and gene therapy is ongoing.
Practical points
Regular laboratory monitoring (liver values) is needed during CFTR modulator therapy. Drug interactions with other medications — especially azole antifungals, macrolide antibiotics and some statins — must be considered. The dose is typically taken with a fat-containing meal (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 open the airways. Inhalation therapy is typically needed daily and takes time.
Airway physiotherapy
Specific techniques for secretion clearance (autogenic drainage, PEP devices, active cycle of breathing techniques). Typically daily. Part of the core of CF treatment.¹
Antibiotics
For pulmonary infections — oral, inhaled or intravenous (for severe exacerbations). First Pseudomonas colonisation is typically eradicated aggressively.
Exercise and sport
Regular physical activity improves lung function, mucus mobilisation and quality of life. Explicitly recommended.
Lung transplantation
Can be the last treatment option in end-stage lung disease. The decision is made individually at a specialised CF centre.
7. Nutrition and digestion
High-calorie: people with CF typically have an increased energy demand. 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 adequately absorbed.
Fat-soluble vitamins: supplementation of vitamins A, D, E and K is typically necessary, as these are not adequately absorbed in pancreatic insufficiency.
Salt intake: people with CF lose more salt than average through sweat. Especially in heat, sport or fever, increased salt intake may be needed.
CFRD: CF-related diabetes typically requires insulin therapy. Regular screening is recommended.
8. Daily life with cystic fibrosis
Daily structure: inhalation, physiotherapy, medication intake, nutrition — the daily treatment burden is substantial and requires discipline and organisation. Digital reminder systems can help.
CF centre: care should typically be provided at a specialised CF centre — usually with check-ups every one to three months.
Hygiene and cross-infection protection: people with CF must observe specific hygiene measures because they are susceptible to lung infections. Contact between people with CF should be avoided due to cross-infection risk (no shared waiting areas).
Transition: the move from paediatric to adult medicine is an important step. Specialised adult CF centres take over care.
Mental health: the high treatment burden, the chronic illness and life planning can affect 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, antibiotic courses — the CF treatment plan is one of the densest there is. brite helps you keep the overview and miss nothing.
Intake reminder — Kaftrio (with fat-containing meal), pancreatic enzymes with every meal, vitamins A/D/E/K, morning and evening inhalations, antibiotic courses: brite reminds you on time of every component.
Drug 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 levels. brite shows the critical combinations.
Health journal — track lung function (FEV1), weight, exacerbations, antibiotics used and treatment adherence over time. At the next CF centre appointment, show what really happened.
Digital medication plan — all medications clearly organised for CF centre, pulmonology, GP and emergency care. In an emergency (e.g. acute exacerbation), treating clinicians see the complete therapy regime immediately.
Medications that act directly on the defective CFTR protein and partially restore its function. The most effective combination is elexacaftor/tezacaftor/ivacaftor (Kaftrio/Trikafta). It can substantially improve lung function, weight and quality of life and has fundamentally changed the prognosis in CF.³
Currently it cannot. CFTR modulators treat the underlying cause at the protein level, but cannot correct the gene mutation. Gene therapy approaches are in research. With modern treatment, however, many people now achieve a largely independent life into adulthood.¹
Autosomal recessively: both parents must be carriers of a CFTR mutation. With each child, there is then a one in four chance of developing CF. Carriers themselves are typically healthy.
The gold standard of CF diagnosis. It measures the chloride concentration in sweat. People with CF have elevated chloride levels in sweat. The test is painless and can typically be performed from infancy.
People with CF typically have an increased energy demand due to chronic inflammation, increased breathing effort and limited nutrient absorption from pancreatic insufficiency. Adequate calorie intake is important for weight, muscle mass and lung function.
Capsules with digestive enzymes (lipase, amylase, protease) taken with every fat-containing meal. They replace the missing pancreatic enzymes and enable nutrient absorption. The dose is adjusted individually.
To avoid cross-infection. Certain bacteria (especially Pseudomonas aeruginosa, Burkholderia cepacia) can be transmitted between people with CF and cause severe lung infections. CF centres therefore recommend separate waiting areas and appointments.
Life expectancy has improved dramatically over recent decades. With CFTR modulators, many people are expected to live substantially longer than previous generations. Concrete figures are difficult to give as the modern therapies have only been available for a few years.
Medical disclaimer: This article is for general information only and does not replace medical advice, diagnosis or treatment. Cystic fibrosis requires specialised care at a CF centre. CFTR modulators have relevant side effects and drug interactions and should only be taken under medical supervision. Last updated: April 2026.
