Genotype and Ultrastructure Correlation in Primary Ciliary Dyskinesia Among Saudi Children: A Case Series

Background: Primary ciliary dyskinesia (PCD) is a rare inherited disorder of motile cilia causing chronic oto-sinopulmonary disease. Transmission electron microscopy (TEM) remains essential for confirming ultrastructural defects, especially in resource-limited settings. This study characterizes the clinicopathologic and molecular spectrum of Saudi children with PCD. Methods: Ten Saudi children with confirmed PCD (2018–2025) were retrospectively reviewed. Clinical, radiological, ultrastructural, and whole exome sequencing (WES) data were analyzed to assess genotype–phenotype correlation. Results: The cohort included seven females and three males (median age 9 years). Consanguinity was present in 80%, and five had situs inversus. TEM showed class 1 defects in 3 patients, class 2 in 2, and abnormalities of uncertain significance in 3. WES identified variants in DNAAF3, DNAAF4, RSPH9, GAS2L2, and NME5. Conclusions: This study expands the molecular and ultrastructural profile of PCD in Saudi Arabia. TEM remains essential for diagnosis and variant interpretation.