CYSTIC FIBROSIS (CF) carrier screening is missing a substantial proportion of at-risk individuals in non-European ancestry groups, with evidence suggesting that commonly used CFTR gene testing panels are increasingly misaligned with global population diversity.
CF is caused by pathogenic variants in the CFTR gene, which disrupt chloride ion transport and lead to progressive multi-system disease, including chronic lung infection. While CF occurs across all ancestries, incidence is highest in Northern European populations.
CFTR Gene Testing Panels Struggle with Ancestry Diversity
The study highlights that most CF carrier screening programmes rely on targeted variant panels or CFTR sequencing approaches. However, current panels are largely designed around variants common in individuals of European ancestry, limiting detection in other groups.
Using Australian registry data and large-scale international modelling, researchers assessed screening performance across ancestry groups and found clear disparities in carrier screening sensitivity and yield. Panels capturing 25–50 variants initially identified around 92–95% of CFTR variants in Australia, but this performance declined over time to approximately 87–92% as population demographics shifted.
International real-world data showed wide variation in detection rates: around 84–90% in individuals of European ancestry compared with 25–69% in Asian populations, 62–91% in Black populations, 51–55% in Middle Eastern groups, and 17–33% in Pacific Islander groups.
Demographic Change Exposes Residual Risk Gaps
Researchers report that increasing population diversity, particularly in Australia, has contributed to reduced effectiveness of fixed variant panels. Migration patterns have expanded the range of CFTR variants in circulation, diluting the representation of historically dominant European variants.
As a result, residual risk after CF screening remains substantially higher in several non-European ancestry groups. The findings suggest that static panel design is unable to keep pace with changing genetic diversity in reproductive-age populations.
Towards Sequencing-Based CF Carrier Screening
The analysis indicates that achieving equitable sensitivity across ancestries would require at least 176 pan-ancestry variants, many of which are not included in current guideline-endorsed panels. Researchers argue that this threshold is difficult to maintain using fixed panels alone.
The study therefore supports either expanding variant lists or transitioning towards CFTR gene sequencing, which would better capture global variant diversity and reduce inequities in carrier detection.
Limitations and Clinical Implications
The authors note limitations including reliance on self-reported ancestry and incomplete subgroup resolution in international datasets. Despite this, the consistency of findings across large datasets strengthens the overall signal.
Clinically, the results suggest that CF carrier screening strategies calibrated to European populations may no longer meet equity goals in increasingly diverse healthcare systems. The findings also imply broader implications for expanded reproductive genetic screening, where variant selection directly influences diagnostic fairness.
Overall, the study highlights a growing need for ancestry-inclusive genomic design to ensure equitable CF carrier screening performance worldwide.
Reference
Gruzin MJ et al. Ensuring equity in reproductive carrier screening of CFTR with increasing population diversity. J Cyst Fibros. 2026;DOI:10.1016/j.jcf.2026.05.001.
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