Demographics of the UK cystic fibrosis population: implications for neonatal screening

Open Access
Publisher Website
Google Scholar
Abstract
The objective was to determine the composition of the Cystic Fibrosis (CF) Population attending specialist UK CF centres in terms of age, gender, age at diagnosis, genotype and ethnicity. With the planned introduction of the national CF screening programme in the UK, cystic fibrosis transmembrane regulator (CFTR) mutations were compared between different ethnic groups enabling a UK-specific frequency of mutations to be defined. Data were analysed from the patient biographies held in the UK CF Database (see www.cystic-fibrosis.org.uk). The currently registered population of 5274 CF patients is 96.3% Caucasian with a male preponderance that significantly increases with age. The majority of the 196 non-Caucasian CF patients are from the Indian Subcontinent (ISC), of which one in 84 UK CF patients are of Pakistani origin. The commonest CFTR mutation, ΔF508, is found in 74.1% of all CF chromosomes. In the Caucasian CF population, 57.5% are ΔF508 homozygotes but the UK ISC CF population with only 24.7%, has significantly fewer ΔF508 homozygotes patients (95% confidence interval (CI) 0.2–0.4). The distribution of Caucasian patients with ΔF508/ΔF508, ΔF508/Other and Other/Other does not fit the expected distribution with a Hardy–Weinberg model unless those patients without a detected mutation are excluded (P80% detection rates in the ethnic minority groups. Screen-positive, non-Caucasian infants without an identifiable CFTR mutation should be referred for a sweat test and genetic counselling when serum trypsinogen concentrations remain elevated after birth.