Cystic Fibrosis (CF) is a transporter disorder. It is hereditary disease that affects the mucus-producing glands and causes a build-up of thick sticky secretions in the lungs and gut. This leads to recurrent chest infections, impaired digestion, and poor growth.
The gene defect for cystic fibrosis is inherited when both parents have the same abnormal gene and unknowingly pass it on to their baby. A parent who has the abnormal gene, but not the disease, is called a carrier. The health of a carrier is rarely affected. However, for each pregnancy of two such carriers, there is a 1 in 4 chance that the child will be born with the disease. CF occurs in about 1 in every 2,500 births in WA.
One in every 25 people in Australia is a carrier of the gene for CF. CF is most common in persons of a Northern European background, but it does also occur in other populations.
The symptoms of CF vary, and some children are less severely affected than others. Most children tend to cough and wheeze frequently and they may develop repeated lung infections, such as pneumonia. Many also have digestive problems due to blockage of digestive enzymes from the pancreas, which causes the child to grow slowly. The sticky secretions in the gut may cause a bowel blockage, called meconium ileus, which occurs in about 15% of babies with CF. The amount of salt in sweat is also increased and this forms the basis of the sweat test used to diagnose CF.
Although there is no cure for CF, early diagnosis and treatment are important as recent medical advances have greatly improved the outlook for children with CF.
Treatment usually involves antibiotics for lung disease, with physiotherapy and aerosols to help clear the airways of secretions. To improve their growth, children with CF are given a high-calorie diet supplemented with vitamins and often need special medications that contain pancreatic enzymes.
The screening test measures the amount of a pancreatic enzyme in the blood, called IRT. Those babies with high levels of IRT then have their screening sample tested to see if they have the CF gene. Any baby who has the CF gene is then recalled for a sweat test. This screening approach will find about 95% of the babies with CF. The test will also find a small number of healthy babies who are carriers of the CF gene.