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About the condition
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CF is a transporter disorder. It is hereditary disease that affects the mucus-producing glands causes accumulation of thick mucus in the lungs and gut. This leads to recurrent chest infections, impaired digestion, and poor growth.
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Inheritance
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Autosomal recessive. About 1 in 25 persons in Australia carries a CF gene.
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Year screening stared in WA
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2000 |
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Incidence in WA
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1 in 2,500 births.
CF is most common in persons of a Northern European background but it does also occur in other populations.
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Defect
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Defective cystic fibrosis transmembrane conductance regulator (CFTR) function.
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Symptoms if untreated
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The symptoms of CF vary, and some children are less severely affected. Most children tend to cough and wheeze and they usually develop progressive lung disease.
Many also have digestive problems due to deficiency of enzymes from the pancreas, which causes the child to grow slowly. The thick secretions in the gut may cause a bowel blockage, called meconium ileus, which occurs in about 15% of neonates with CF. Other symptoms of the condition include liver disease, diabetes mellitus, and impaired fertility (CBAVD).
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.
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Metabolites on bloodspot screening
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- Increased immunoreactive trypsin (IRT)
- Common CFTR variant analysis in those with IRT>99% (tested for p.Phe508del, p.Gly551Asp, p.Gly542*, and c.489+1G>T)
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Diagnostic tests
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- Sweat test
- Extended CFTR gene analysis
- Clinical assessment and genetic counselling
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Treatment
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- The aim of screening is to reduce morbidity by early diagnosis and treatment of lung infections, and attention to good nutrition. There are now also specific drug therapies for some children with CF.
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Screening issues
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- In WA, approximately 95% of infants with CF carry one of the four common CFTR variants (as listed above)
- The screening strategy will also detect a small number of healthy carriers of CF
- Notify the screening program of any baby with meconium ileus or a family history of CF to ensure CFTR variant analysis is performed, irrespective of the IRT result
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