Cystic fibrosis in Iceland and the high prevalence of the N1303K variant.

BACKGROUND: Cystic fibrosis (CF) is most common in populations of Northern European ancestry where the F508del variant predominates. In 2020, Iceland became a member of the European Cystic Fibrosis Society Patient Registry, and we launched an epidemiological study of CF in Iceland. The study aimed to determine the prevalence and the genetic variants present in the country. Furthermore, we aimed to describe the previous and the current situation regarding lung function, infections, complications, treatment, and follow-up to understand the strengths and weaknesses of CF care in Iceland.

METHODS: This retrospective study included all individuals in Iceland with a confirmed CF diagnosis between 1955 and 2021. We conducted a medical records search for CF diagnosis codes and found 30 people with CF who were included in the study. Two hundred sixteen clinical variables were registered. A descriptive analysis of these was performed.

RESULTS: The prevalence of CF in Iceland is 0.372:10,000 inhabitants. The F508del is the most common CF transmembrane conductance regulator (CFTR) variant (46.4%), closely followed by N1303K (44.6%). Staphylococcus aureus was the most common airway pathogen, followed by Pseudomonas aeruginosa. Nasal polyps and CF-related diabetes were the most common complications. Modern CF medications, including the recent CFTR modulators, are available.

CONCLUSION: Even though Iceland has a relatively low prevalence of CF, it holds the highest known prevalence of the N1303K variant in Europe. Access to necessary treatment is satisfactory, but improvements are advisable for some aspects of the routine assessments by best practice guidelines.