Cystic fibrosis is a genetic condition in which the lungs and digestive system become clogged with thick sticky mucus.

Symptoms usually start in early childhood and include:

• persistent cough
• recurring chest and lung infections
• poor weight gain

An early sign is that an affected child’s sweat is unusually salty, which can be noticeable when you kiss your child. 

However, most cases of cystic fibrosis in the UK are now identified through screening tests carried out early in life, before symptoms appear.

Read more about the symptoms of cystic fibrosis.

Treating cystic fibrosis

As there is no cure for cystic fibrosis the aim of treatment is to ease symptoms and make the condition easier to live with. For some rare types of cystic fibrosis, such as the G551D mutation, there are treatments which aim to compensate for a defective gene.

Treatment can also prevent or reduce long-term damage caused by infections and other complications.

Treatment options include:

• antibiotics – to treat chest and lung infections
• physiotherapy – a range of exercises can help clear mucus from the lungs
• bronchodilators – a type of medication that helps expand the airways inside the lungs, making it easier to breathe
• inhaled mucus-clearing treatments – such as pulmozyme, hypertonic saline (a strong salt solution) and mannitol dry powder

In some cases a lung transplant may eventually be required if the lungs become extensively damaged.

Read more about treating cystic fibrosis.

What causes cystic fibrosis?

Cystic fibrosis is caused by a genetic mutation; specifically a mutation in a gene called CFTR. A genetic mutation is when the instructions found in all living cells become scrambled in some way, meaning that one or more of the processes of the body do not work in the way they should.

The CFTR gene normally creates a protein that regulates levels of sodium and chloride in cells. If the CFTR gene is defective, it results in a build-up of thick, sticky mucus in the body's tubes and passageways. These blockages damage the lungs, digestive system and other organs, resulting in the symptoms of cystic fibrosis.

Read more about the causes of cystic fibrosis.

Who is affected

Cystic fibrosis is most common in white people of northern European descent.

It is estimated that one in every 2,500 babies born in the UK will be born with cystic fibrosis and there are more than 9,000 people living with the condition in this country.

The condition is much less common in other ethnic groups.

Diagnosis

Cystic fibrosis is one of the conditions babies are screened for with the newborn blood spot test.

A small amount of the baby's blood is taken by a heel prick and transferred onto a card. The blood sample on the card is then analysed in the laboratory for cystic fibrosis and eight other conditions, including sickle cell anaemia.

Read more about how cystic fibrosis is diagnosed.

Outlook

In the past, most children with cystic fibrosis would die of related complications before reaching adulthood.

The outlook has improved considerably in recent years due to advancements in treatment, although most people with cystic fibrosis will have a shorter than average life expectancy.

It is now estimated that, on average, children born in the 21st century with cystic fibrosis will live for more than 50 years.

Genetic disorder

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

Carrier

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