VOL: 101, ISSUE: 19, PAGE NO: 52What is it?
What is it?
- In cystic fibrosis the body produces a defective version of a protein called cystic fibrosis transmembrane conductance regulator (CFTR).
- Defective CFTR causes the body to produce a thick mucus, which obstructs the lungs causing life-threatening lung infections.
- These secretions also affect the pancreas, preventing digestive enzymes from reaching the intestines where they normally help break down food.
- Cystic fibrosis is the result of an abnormal gene, carried by approximately 1 in 25 people.
- Two copies of the abnormal gene are required to develop cystic fibrosis. People with one affected gene and one unaffected gene are carriers and will not develop cystic fibrosis.
- If a carrier has a child with another carrier, then the chance of the child inheriting two affected genes is 25 per cent. This happens once in every 2,500 live births, resulting in approximately 250 cystic fibrosis births in England and Wales every year.
Symptoms can vary because of the more than 1,000 mutations of the gene. Symptoms include:
- Failure of infants to thrive;
- Lung problems, including persistent coughing, phlegm and shortness of breath;
- Pancreatic enzyme problems, causing difficulties with the bowel's absorption of nutrients;
- Excessive appetite, but poor weight gain;
- Very salty-tasting skin;
- Sinusitis and nasal problems;
- Greasy, thick stools;
- As they age, people with cystic fibrosis are also prone to bronchiectasis, bowel obstruction, infertility and liver cirrhosis.
- Osteoporosis can be a problem because of the steroids taken to control lung disease.
- Some babies have a bowel obstruction called meconium ileus, where, the meconium (thick black matter present in the bowels of all newborns) is so thick that it does not pass through the bowel. An operation is needed to relieve the blockage.
- Dietary problems can lead to type 2 diabetes.
- New-born testing - babies can be blood tested at birth using a heel prick test.
- Sweat test - children with cystic fibrosis have higher levels of salt in their sweat than normal.
- Antenatal testing - this can determine early on in a pregnancy whether the baby will have cystic fibrosis. It is only offered in cases where there is a high chance of the condition being present.
- Genetic testing - a sample of cells can be obtained from inside the cheek and used to isolate the cystic fibrosis gene.
- Lung X-ray - this can ascertain whether there has been damage due to cystic fibrosis.
- Chorionic villus sampling is a genetic test for prenatal diagnosis. It is normally performed between the 9th and 12th weeks of pregnancy and allows parents to decide whether or not to continue with the pregnancy.
The main aim of treatment is to prevent respiratory infections - the most common cause of death.
- Antibiotics to treat infections.
- Physiotherapy is used to clear mucus from the lungs. Eventually patients can do this themselves.
- Bronchodilators open the airways and steroids are used to reduce airway inflammation.
- Bowel absorption problems mean good diet is vital. Enzyme supplements are used to help the pancreas absorb nutrients and provide more energy.
- Exercise helps prevent deterioration of the lungs and develops all-round strength.
- Heart-lung transplantation is an established treatment for end-stage cystic fibrosis.
- The isolation of the cystic fibrosis gene has meant researchers are trying to correct the defect rather than addressing the symptoms, but this is still at an early stage.
Cystic Fibrosis Trust: www.cftrust.org.uk/index.jsp