Three Cases of Primary Ciliary Dyskinesia Combined With Reduced Exhaled Nitric Oxide

Objectives: The diagnosis of primary ciliary dyskinesia (PCD) is often delayed in part related to the limitations of the available diagnostic tests. We present 3 cases of PCD diagnosed using an exhaled nitric oxide (eNO) measurement. Methods: Three cases with a clinical phenotype consistent with PCD were evaluated using an eNO assay with additional transmission electron microscopy (TEM) and/or genetic panel testing. Results: One male and 2 female patients presented with common symptoms included recurrent respiratory infection from early childhood and a history of neonatal respiratory distress as term newborn. Two of them had situs inversus totalis. Fractional eNO measurement revealed extremely low NO levels, and subsequently, TEM analysis confirmed ciliary ultrastructural defects in all patients. One patient had compound heterozygous mutation of the PCD-causative gene (DNAH5) identified using next generation sequencing. Conclusion: Our report stresses the reliability of eNO measurement in the diagnosis of PCD, accompanied by clinical phenotypes and additional diagnostic tools, such as TEM analysis and genetic testing.