Diagnosis of primary ciliary dyskinesia: Current practice and future perspectives

PCD is a genetically and clinically heterogeneous condition. It is characterised by inherited abnormality of motile ciliary function. Symptoms include recurrent upper and lower respiratory tract infections from an early age, usually resulting in bronchiectasis as an adult. Approximately 50% of people with PCD have situs inversus. Diagnosis of PCD is complex and requires a multi-test approach since no test has complete sensitivity or specificity. This chapter describes the central aspects of PCD diagnosis, based on evidence from the 2017 European Respiratory Society guidelines. Diagnostic investigations include measurement of nasal nitric oxide, genetic testing and sampling the nasal epithelium to conduct microscopic analysis of cilia. Laboratory microscopy investigations include ciliary beat frequency and pattern by high-speed video microscopy, ciliary protein expression by immunofluorescence, and ciliary ultrastructure by transmission electron microscopy. A diagnosis is confirmed by the presence of a hallmark defect of ciliary ultrastructure observed by electron microscopy or bi-allelic pathogenic mutations in a known PCD gene.