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Cystic Fibrosis

What is Cystic Fibrosis?

Cystic Fibrosis (CF) is a genetic disease which results in unusually thick mucus.

This can cause many different problems in the body.

Lungs

The mucus clogs the tiny airways in the lungs and traps bacteria causing repeated infections and lung damage.

Gut

In the gut, the thick mucus prevents normal digestive enzymes to flow into the bowel. This causes incomplete digestion and malabsorption which can affect the growth of the baby and child.

CF is a serious but variable disease which requires regular and continuous treatment.

The severity of the lung disease is the key to the quality and the length of life. -

These days an affected person usually lives well into their 30s and beyond.

Of those who succumb, it is usually due to lung complications.

How do you inherit CF?

CF is an inherited disease. For a child to be born with CF both parents must be carriers of the CF gene mutation.

Our genes work in pairs, with a copy of the CF gene on each chromosome number 7.

Carriers have one faulty copy on one chromosome. Carriers do not have CF or any symptoms of the disease.

A person affected with CF has two faulty copies, one on each chromosome 7 received from each parent.

How common is CF?

About one in 2500 babies in Australia is born with CF.

One in 25 Caucasians are carriers of a CF gene mutation.

If a person who is a CF carrier has partner who is also a carrier, they have a 1 in 4 chance of having a child with CF.

This kind of inheritance is called "autosomal recessive." It is not related to the sex of the baby.

Over 85% of couples with children affected by CF have no family history of the disease because the gene mutation is silently passed down through generations.

If you do have a family history, then the risk is greater. Please tell your doctor if this is the case.

Why do we offer couple testing?

In the USA, this screening is offered to all couples either pregnant or considering a pregnancy.

In Australia it is screened for routinely after birth on a heel prick of the newborn baby.

But it is possible to find out your risks early in pregnancy.

We think couples will want answers to these important questions:

Am I a carrier?
Is my partner a carrier?
Will my baby be affected?

We are able to test for the most common fault, or mutation that carriers of CF may have. It is called delta F508.

We can also do an extended panel of 30 or so mutations if needed.

If both of you are negative

for the ▲ F508 mutation the chance of you having a baby with CF is reduced to 1 in 35,000. A small risk remains but because we cannot check for all the mutations.

If both of you are carriers of the ▲ F508 mutation there is a 1 in 4 chance of an affected child.

This knowledge opens up a variety of options, one of which is prenatal diagnosis.

This could mean chorionic villus sampling to test the fetus itself for cystic fibrosis.

These choices would be discussed with you, as a couple, to help you make the decision that suits you both.

Cystic fibrosis carrier testing

A simple mouthwash will identify 75% of people who are carriers
1 in 25 people of Caucasian descent are carriers
It is less common in people of other descent
Carriers are perfectly healthy
If both partners are carriers there is a 1 in 4 chance of having a child with cystic fibrosis
If only one partner is a carrier of the ▲ F508 mutation, the chance of having a child with CF is 1 in 400
Testing is best performed before pregnancy, but can be performed in early pregnancy.
Test results take about 2 weeks
The costs are approximately $75.00 for ▲ F508 testing alone and $250.00 for the 30 most common mutations
After birth all babies in Australia are screened for cystic fibrosis and several other conditions on a heel prick test