In people with cystic fibrosis, the defective gene causes a thick, sticky accumulation of mucus in the lungs, pancreas and other organs. In the lungs, the mucus clogs the airways and traps bacteria leading to infection, leading to extensive lung damage and ultimately respiratory failure.

Symptoms of cystic fibrosis

People with cystic fibrosis can have a variety of symptoms, including but not limited to:

• thick and sticky mucus, lodging in the bronchi and blocking the pancreatic ducts;
• persistent cough, shortness of breath;
• frequent lung infections, including pneumonia or bronchitis;
• chronic sinusitis with polyps (mainly in older children and adults);
• possible nasal polyps and haemoptysis;
• chronic infection with Pseudomonas aeruginosa (blue pus bacillus) and Staphylococcus aureus (staphylococcus aureus );
• delayed physical development (weight and height deficiency);
• frequent fatty, bulky stools or difficulty in defecation;
• enlargement of the abdomen, sometimes rectal prolapse;
• meconium ileus in the neonatal period (often the first sign of cystic fibrosis);
• cholelithiasis;
• recurrent pancreatitis;
• intestinal torsion in the fetal period;
• plugging of the salivary ducts with thick mucous secretions;
• impaired muscle development (e.g. absence of gluteals);
• excessive fatigability (rapid fatigue on exertion).

Diagnosis and genetics

Early diagnosis plays an important role in the treatment process. Diagnosis is mainly made through a screening test. This test began to be introduced in Poland as early as 1999. Currently, all newborns born in Poland undergo this procedure. It involves collecting a few drops of blood from the newborn on filter paper, which, after being marked with a special code, is then sent to a laboratory specialising in screening tests.

Diagnosis can also be made on the basis of:

• the clinical picture of the patient, i.e. the symptoms that usually occur with cystic fibrosis;
• measurement of the concentration of sodium chloride in sweat (people with cystic fibrosis have a so-called "salty sweat");
• a genetic test that directly identifies mutations in the CFTR gene on both chromosomes. With these tests it is possible to determine the carrier of cystic fibrosis, which also makes it possible to assess the risk of having a child with cystic fibrosis.

photo: panthermedia

People with cystic fibrosis inherit two copies of the defective gene - one copy from each parent.

People with only one copy of the faulty gene are called carriers, but do not have the disease. Whenever two carriers have a child, the chances are:

• 25 per cent (1 in 4) the child will have cystic fibrosis;
• 50 per cent (1 in 2) the child will be a carrier but will not have cystic fibrosis;
• 25 per cent (1 in 4) the child will not be a carrier and will not have cystic fibrosis.

A defective gene contains a small abnormality called a mutation. There are more than 1,700 known mutations of the disease. Most genetic tests only test for the most common mutations. Therefore, the test results may not always be 100% effective.