Cystic fibrosis

Cystic fibrosis (CF) is the most common potentially lethal autosomal recessive disorder in Caucasian populations, characterised by chronic suppurative lung disease and chronic exocrine pancreatic insufficiency.

It affects 1 in 2500 infants and the frequency of carrier heterozygotes is estimated to be 5%.

Cystic fibrosis is a multi-system genetic disorder affecting the lungs, pancreas, liver and intestine. It can have a significant impact on life expectancy and quality of life (1).

• Current median age of those who have died is 28 years and the median predicted survival is 45.1 years.
  
• Diagnosis is primarily made during newborn screening.
  • median age at diagnosis is 2 months, and 1 in every 2500 babies born in the UK has cystic fibrosis.
    
• Approximately 60% of people on the UK cystic fibrosis registry are aged over 16 years.

The predominant symptoms of CF are attributed to epithelial abnormalities in the respiratory, digestive and reproductive tracts:

• although lungs are normal at birth, recurrent respiratory infection is a major presenting feature
• 85% of CF patients have pancreatic insufficiency
• 10% of CF newborns suffer meconium ileus
• patients are also prone to hepatic cirrhosis and male infertility.

There are many different mutations responsible for cystic fibrosis (1).

• UK registry shows that 90.8% of people with cystic fibrosis have one known genotype; however 8.9% of people have at least one unknown genotype.

Lung function is often reduced in cystic fibrosis (1):

• typical measure of lung function is forced expiratory volume in 1 second (FEV1)
• FEV1 is a key predictor of life expectancy in people with cystic fibrosis, and optimising lung function is a major goal of care.

Lung infections are a cause of significant morbidity in cystic fibrosis (1):

• chronic infection (for example with Staphylococcus aureus and Pseudomonas aeruginosa) may need long-term use of antibiotics.

Based on the last UK National Screening Committee (NSC) review that occurred in August 2019, screening during pregnancy is not currently recommended for this condition (2):

• many genes play a role in causing cystic fibrosis, which makes it difficult to know which ones to screen for
• no new evidence to support screening all women during pregnancy.

Reference:

• (1) NICE (October 2017) Cystic Fibrosis. Available at https://www.nice.org.uk/guidance/ng78. (Accessed on 05 June 2022)
• (2) UK National Screening Committee (2019) Cystic Fibrosis (pregnancy). Available at https://view-health-screening-recommendations.service.gov.uk/cystic-fibrosis-pregnancy/. (Accessed on 05 June 2022)