Cystic fibrosis

Cystic fibrosis (CF) is a condition that affects many organs in the body: especially the lungs, pancreas and sweat glands. People affected by CF produce abnormally thick, sticky mucus, particularly in the lungs and digestive system. Intelligence is not affected in people with CF.

While it is normal to have mucus lining the organs of the respiratory, digestive, and reproductive systems, in people with CF this mucus is thick and sticky which can trap infections in the lungs leading to progressive lung damage. Digestion is affected as the body cannot extract nutrients from the normal diet, this can be improved by taking enzyme supplements however, commonly people with CF struggle with maintaining healthy weight despite a good appetite and balanced diet. Finally, the sweat glands also secrete sweat that is very high in salt, thereby depleting the body of this important substance.

The severity of symptoms varies from person to person, even among individuals in the same family and/or with the same gene variations. Males with CF may also appear infertile. This is because most men with CF are missing the tubes that transport sperm from the testicles out through the penis - this is called congenital absence of the vas deferens (CAVD). Men with CF still produce normal mature sperm and thus infertility can be overcome using IVF.

Quick facts about cystic fibrosis
Genes: CFTR
Inheritance: Autosomal Recessive
Alternative Names: CF, CFTR
Relevant resources for cystic fibrosis

A quick genetics rundown

As humans we have about 23,000 genes. These genes are like tiny instruction manuals that influence our health, growth and development. We inherit half of our genes from our biological mum and the other half from our biological dad. These genes are lined up on structures called chromosomes. Most of us have 23 pairs of chromosomes. The first 22 pairs are called autosomes and for the most part - these are the same among men and women. The 23rd pair determine our sex - two X chromosomes for a female and one X and one Y chromosome for males.

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How is cystic fibrosis inherited?

cystic fibrosis is known as an autosomal recessive condition. For autosomal recessive conditions, if a person has a variation in one copy of their gene, they are a carrier. This means that they are healthy because they also have a working copy of the gene. But, they can still pass their non-working copy to their child.

If the other parent also happens to be a carrier of the same gene, there is a 25% (1 in 4) chance that they both pass this gene variation on to their child — and as such, have a child affected by the disease.

If both parents are carriers of cystic fibrosis, there’s a one in four chance that their children could develop symptoms.
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What is carrier screening?

Carrier testing is like a checkup for your genes. It tests to see if you carry a gene variation that could cause a serious genetic disease in your child. Eugene offers an inclusive genetic carrier screening panel that includes cystic fibrosis, but there's a total 301 conditions that can be tested.

Eugene’s carrier test is a clinical grade test that can be done from the comfort of your own home — it’s just a saliva test. You're also paired with a genetic counsellor who provides mindful support and guidance every step of the way.

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Should parents screen for cystic fibrosis before or early in pregnancy?

The biggest benefit of screening for cystic fibrosis is that it can help future parents understand their reproductive risk so they can be ready and empowered to make more informed decisions. If neither partner are carriers, it provides reassurance and peace of mind that the risk of having a child with a genetic disease is low.

Since 90% of children that have a recessive genetic disease like cystic fibrosis had no previous family history of it, it often feels completely out of the blue for the parents. Getting screened is a way to know this risk in advance, which can help familes manage or even prevent the disease in the first place.

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