Genetics and Incidence
CF is a genetic disorder. If a child has one copy of a CF gene, they are carriers of the gene. If the child has two copies of a CF gene, they will have CF.
If both parents carry a CF gene each (carriers) there is a 1 in 4 chance their child will be born with CF, and a 1 in 2 chance their child will be a carrier of the CF gene. This is the case for every pregnancy these parents have. If one parent has CF and one parent has two normal genes, then all of the children will be carriers.
Your child will have had a newborn heel prick test which screens for the CF gene, every child born in Australia has this test. If the gene is found on this test, they will also have a sweat test to decide on a formal diagnosis of CF. The sweat test is pain free to your baby but it does take a little bit of time and you will have to go to the hospital for this to be done. The sweat test measures the amount of chloride in your baby’s sweat. If this is positive your baby will also have a blood test to confirm the CF genes they carry.
The most common genetic mutation in CF is delta F508. To have CF your child needs to have a CF gene from each parent. They may be the same mutation (homozygous) or your child may have what is called a heterozygous combination which means they have two different mutations.
New treatments (called CFTR modulator therapy) are available, and there will be more on the horizon. CFTR modulator therapy targets the CFTR protein and aims to change how it is working. The CFTR modulator therapies available now may not be suitable for your child but the world CF research community are very focused on not leaving anyone behind in their vision to develop modulator therapy for all. Your child may have the correct mutations for current therapy but they may need to wait until they are a little older before they commence on these therapies.
Important things to note about CF incidence are:
- Males and females are affected equally
- Over 2000 different types of genetic mutations cause CF
In Australia and New Zealand, one in 25 people, or nearly one million people in total, are carriers of the CF gene. Approximately one in every 3000 babies are born with CF, with a new diagnosis occurring approximately every 4 days.