Longitudinal Lung Volume Changes by Ultrastructure and Genotype in Primary Ciliary Dyskinesia

Rationale: Genotype-phenotype relationships are emerging in primary ciliary dyskinesia (PCD), but little is known about lung volume changes over time. Objectives: To investigate the evolution of static lung volumes with ultrastructural defects, gene mutations, body mass index, and specific infections in PCD. Methods: Prospective, longitudinal, single-center study in children and adults evaluated twice yearly for up to 10 years. Linear mixed-effects models were used to assess associations between ciliary morphology, genetic mutations, and clinical features. Results: A total of 122 patients had 1,096 visits. At enrollment, almost all spirometric and, especially in adults, plethysmographic parameters were significantly worse in absent inner dynein arms (IDAs), central apparatus (CA) defects, and microtubular disorganization (MTD) (IDA/CA/MTD) compared with patients with normal electron microscopy (EM) results. The mean trend increase with time for residual volume (RV) was significantly higher in IDA/CA/MTD group compared with groups with outer dynein arm defect and normal EM results. The mean trend of RV/total lung capacity in the IDA/CA/MTD group was significantly worse than in all other groups. The steepest rise in lung volumes was in CCDC39 and CCDC40, whereas hyperinflation increased less in DNAH5 and DNAH11 groups. RV/total lung capacity showed a significantly steeper rise in patients with Pseudomonas aeruginosa compared with patients with other infections or patients without infection. Conclusions: Patients with IDA/CA/MTD defects or CCDC39 and CCDC40 mutations had the greatest increase in hyperinflation, whereas those with outer dynein arm defect and normal EM results or DNAH11 and DNAH5 mutations had less severe changes. We have robustly confirmed the worse prognosis for some genetic and ultrastructural defects, which association hitherto rested solely on spirometry.

Automated summary

This study investigated the evolution of static lung volumes in patients with PCD over a 10-year period, and found that patients with absent inner dynein arms and certain gene mutations had significantly worse lung function at baseline. The trend of lung volume increase over time was influenced by ultrastructural defects and genetic mutations.