Estimates of primary ciliary dyskinesia prevalence: a scoping review

Primary ciliary dyskinesia (PCD) is a rare multi-system genetic disease caused by dysfunctional motile cilia. Despite PCD being the second most common inherited airway disease after cystic fibrosis, PCD continues to be underrecognized globally due to non-specific clinical features, and the lack of a gold standard diagnostic test. Commonly repeated prevalence estimates range from 1-in-10,000 to 1-in-20,000, and based on regional epidemiologic studies with known limitations. The purpose of this scoping review is to appraise the PCD literature, to determine the best available global PCD prevalence estimate and to inform the reader about the potential unmet health services needs in PCD.To systematically review the literature about PCD prevalence estimates.A scoping review was conducted following the PRISMA-ScR methodology. Included studies estimated PCD prevalence and used cohort, clinical or genomic data. Excluded articles were case reports, conference abstracts, review articles, animal studies or non-English articles.Literature review identified unique abstracts. Thirty-four underwent full text review and 8 met the inclusion/exclusion criteria. Seven articles were based on epidemiologic studies of specific geographical regions and provided prevalence estimates that ranged from ∼1 to 44.1-in-100,000. Only one study estimated global prevalence, using two large genomic databases, and calculated it to be ∼13.2-in-100,000 (based on pathogenic variants in 29 disease-causing genes).A population based genomic approach for estimating global prevalence has found that PCD is much more prevalent than previously cited in the literature. This highlights the potential unmet health service needs of people living with PCD.