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What is CF?

Cystic fibrosis (CF) is the most common life threatening genetic condition affecting New Zealand children. It is a genetically inherited condition some people are born with that mainly affects their lungs and digestive system.

Cystic fibrosis is caused by a faulty gene that has been passed down from a baby's mum and dad and is usually diagnosed soon after birth.

Genes are what make us who we are – they affect our eye colour, hair colour, how tall we are and many of the things that make us individuals. Genes also affect how our body works on the inside, and changes in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene causes CF. 

Every person has two copies of their genes – one from their father and one from their mother. Many people carry one copy of the CFTR gene (often called the ‘CF gene’) but you need two copies to be born with CF. Having one copy does not affect your health.

When we don’t have CF, our bodies make mucus that is thin and slippery and works as a lubricant to help protect us from infections and to keep the inside of our body working well.

If we have CF, our mucus becomes thick and sticky and blocks the tiny tubes of many of our organs.

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How does it affect the body?

In the lungs, the sticky secretions are difficult to cough up and viruses, bacteria and fungus can become trapped under the mucus. This can cause inflammation and infection, making it harder to breathe and often causing a chronic cough and repeated chest infections. People with CF also have a much higher risk of developing serious complications from bugs that are generally harmless to other people.

In the digestive system, thick secretions also block the flow of digestive enzymes from the pancreas to the duodenum (top part of the intestine), where they are needed to help break down food. Without these enzymes, fats and vitamins can’t be absorbed causing problems with malnutrition and poor weight gain.

There is no cure, but the gene that causes CF has been identified and new research and medications that focus on ways to repair or replace the gene are very promising. There is every reason to be hopeful of a cure in the future.

What are the symptoms?

Most babies in New Zealand are screened for CF at birth and are diagnosed before any symptoms develop. If a child has missed routine screening, symptoms at birth can include:

  • salty tasting skin
  • slow weight gain or failure to thrive even with a good appetite
  • wheezing, coughing and pneumonia
  • abnormal bowel movements.

The type and severity of symptoms varies between individuals – some people with CF remain well for a long period of time with minimal symptoms or hospital admissions, while others require more intensive medical care.


Most people with CF will develop some severity of lung damage over time causing:

  • recurrent chest infections
  • breathlessness
  • wheezing
  • a chronic cough.
Find out how CF is managed with physiotherapy

Digestive system

The lack of digestive enzymes in the duodenum caused by thick mucus causes:

  • malnutrition due to malabsorption
  • poor weight gain
  • frequent, foul-smelling, greasy bowel motions
  • stomach aches
  • excessive wind.
Find out how CF is managed with treatment and medication
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Other organs affected

CF can also affect other parts of the body, such as

  • ears, nose and sinuses
  • liver function
  • bones and joints.

Over time some people with CF can develop CF related diabetes and puberty is often delayed in adolescents.

In most men with CF, the tubes that carry sperm are blocked, or have never developed – known as absence of the van deferens. This can cause fertility problems but does not cause sexual impotence.

Women with CF may have irregular menstrual cycles related to nutritional issues, but they produce healthy, fertile eggs.

CF doesn’t affect a person’s intelligence or mental ability.