Definition: what is cystic fibrosis?
Cystic fibrosis, also known as mucoviscidosis, is a genetic disease. It’s less common name comes from the terms “mucus” and “viscous”. This is because it involves viscous secretion around the organs, causing serious damages and infections. The lungs and the pancreas are generally the most often affected by the disease.
Cystic fibrosis is the most common rare hereditary disease in Europe. It is estimated that 70,000 people are affected in the world.
Causes of cystic fibrosis: genetic origin
The gene responsible for cystic fibrosis is the CTFR gene (cystic fibrosis transmembrane conductance regulator), which codes the protein synthesis of the same name, and is present in the chromosome 7. It is a recessive gene, meaning that the disease appears, only if both healthy parents have carried an allele with a mutation.
The CTFR protein is a chloride ion transporter channel between the inside and the outside of cells of different mucus membranes. The cell mutation creates a defect in the synthesis of the protein, preventing this channel from functioning normally. This causes a lack of hydration around the mucus membranes and therefore a hyper-viscosity in the secretion of mucus. This is the phenomenon which causes the symptoms of cystic fibrosis to appear.
Symptoms of cystic fibrosis
In the majority of cases, cystic fibrosis is diagnosed at birth, or quite early on in infancy. The functions in the body that are mainly affected, are the respiratory and digestive functions. Thickening of mucus secreted first obstructs the lungs and bronchi, which leads to breathing difficulties such as pneumonia or pneumothorax. In addition, this creates a perfect place for the bacteria responsible for infections to grow, such as staphylococcus aureus or the haemophilus influenza.
Patients also suffer a pancreatic insufficiency. The digestive fluids around the pancreas area aren’t sufficiently secreted, which causes a fat malabsorption and a bad digestion. The consequences are abdominal pains, diarrhoea, constipation or growing problems.
There are also various secondary symptoms, varying according to the disease: diabetes, heart problems, cirrhosis.
Diagnosis of cystic fibrosis
Testing for cystic fibrosis is carried out in all new-borns. On the third day of life, a drop of blood is taken in order to measure the enzyme known as trypsin. Beyond a certain rate, the search for the most common mutations of the CFTR gene is carried out. It is also possible, if desired, to do a prenatal diagnosis.
If the disease is not diagnosed at birth, there is also a sweat test which has a success rate of 90%. This involves determining the concentration of chloride and the minimum age required for the patient to have this test is five weeks. When the results come back positive, blood is taken to further look for mutations.
Treating cystic fibrosis: an increasing life expectancy
Nowadays, there is no curative treatment for cystic fibrosis, but research has greatly increased in the last decades. This has considerably increased the quality of life for those who suffer. In the UK, this expectancy has increased from 7 years in the 1960s, to around 45 years in 2008.
The treatment proposed is symptomatic and is mainly based on managing breathing difficulties but is also based on nutritional monitoring and psychological support. It therefore requires a number of specialists to confer.
Caring for cystic fibrosis is particularly strenuous and demanding. This therefore puts significant limitations on the sufferer as well as on their family.