Primary Ciliary Dyskinesia from Embryogenesis to Adulthood: Micro-CT Analysis of Stage-Dependent Upper Airway Abnormalities in Odad3 Loss-of-Function Mouse Models

Background/Objectives: Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by impaired ciliary function, leading to chronic airway disease. Lossof- function mutations in ODAD3 (CCDC151) represent an established cause in patients, and Odad3-deficient mice recapitulate key disease traits. However, the impact of Odad3 ablation on upper airway development and function remains unexplored. This study investigated the consequences of Odad3 disruption on upper airway structures during development and in adult animals. Methods: Constitutive (Odad3−/−) and inducible conditional (Odad3icKO) mouse models were analyzed alongside heterozygous and wild-type littermates during embryonic, postnatal, and adult stages. Optimized high-resolution 3D micro-computed tomography (micro-CT or μCT) combined with histology was utilized to conduct systematic genotype-phenotype evaluations, map upper airway anatomical architecture, and assess PCD disease onset. Results: Genetic dissection revealed a marked dependence of the phenotype on whether Odad3 loss occurred during development or in adulthood. Constitutive Odad3 deletion resulted in pervasive craniofacial remodeling and turbinate hypoplasia during embryonic stages and early postnatal development. Conversely, adult-induced conditional ablation produced localized caudal atrophy of the nasal turbinates accompanied by massive mucus accumulation, consistent with impaired mucociliary clearance and providing a 3D structural and morphological characterization of chronic rhinosinusitis-like pathology in PCD mouse models. Heterozygous Odad3icKO/+ and Odad3+/− mice were phenotypically indistinguishable from wild-type controls, indicating that single-allele loss does not disrupt upper airway morphology. Conclusions: This study characterizes the structural timeline of upper airway pathology in PCD and validates the Odad3icKO model as a robust 3D structural phenotyping platform for investigating airway disease in ciliopathies. Combining targeted genetic disruption with 3D μCT virtual histology offers a powerful framework for comprehensive studies of human genetic variants and gene knockouts in mouse models of PCD.