Cystic fibrosis is an inherited condition in which the lungs and digestive system can become clogged with thick, sticky mucus.

Itcan cause problems with breathing and digestion from a young age. Over many years, the lungs become increasingly damaged and may eventually stop working properly.

Most cases of cystic fibrosis in the UK are now identified through screening tests carried out soon after birth. It's estimated that 1 in every 2,500 babies born in the UKhas cystic fibrosis.

A number of treatments are available to help reduce the problems caused by the condition,but unfortunately averagelife expectancy is reduced for people who have it.

This page covers:

Symptoms of cystic fibrosis

Causes of cystic fibrosis

Screening and testing for cystic fibrosis

Treatments for cystic fibrosis

Outlook for cystic fibrosis

Cystic fibrosis

Symptoms of cystic fibrosis

Symptoms of cystic fibrosis tend to start in early childhood, although they can sometimes develop verysoon after birth, or may not be obvious until adulthood.

Some of the main symptoms of cystic fibrosis can include:

  • recurring chest infections
  • difficulty putting on weight
  • frequent, wet-sounding coughs
  • diarrhoea
  • occasional wheezing and shortness of breath

People with the condition can also develop a number of related conditions, including diabetes ,thin, weakened bones ( osteoporosis ) and liver problems.

This, along with recurrent infections, can result in a build-up of thick, sticky mucus in the body's tubes and passageways.

To be born with cystic fibrosis, a child has to inherit two copies of this faulty gene one from each of their parents. Their parents will not usually have the condition themselves, because they will only carry one faulty gene and one that works normally.

If both parents carry the faulty gene, there's a 25% chance that each child they have will be born with cystic fibrosis.

Screening and testing for cystic fibrosis

Most cases of cystic fibrosis are now detected soon after birth through the newborn blood spot test .

This involves collecting a drop of blood from the baby's heel and testing it forabnormalities that could indicate cystic fibrosis.

More testswill be needed to confirm the diagnosis, such as:

  • a sweat test to measure the amount of salt in sweat, as the sweat of someone with cystic fibrosis has higher levels of salt than normal
  • a genetic test where a sample of blood or saliva is checked for the faulty gene that causes cystic fibrosis

These tests can also be carried out in older children and adults with symptoms of cystic fibrosis who haven't been screened previously.

If you have a family history of cystic fibrosis, you can be tested to determine if you're at risk of having a child with the condition by checking if you're a"carrier" of the faulty gene that causes it.

Currently, about half of the people with cystic fibrosis will live past the age of 40. Children born with the condition nowadays are likely to live longer than this.

Information about you

If you or your child hascystic fibrosis, your clinical team will pass information about you/your childon to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the register .

Genetic disorder

A genetic disorder is a disorder caused by a fault in the genes. It is usually hereditary (runs in the family).


A carrier is a person or animal that spreads an organism that causes disease but does not become ill themselves.

Content supplied by the NHS Website

Medically Reviewed by a doctor on 28 Nov 2016