Primary Ciliary Dyskinesia

Abstract

Primary ciliary dyskinesia (PCD) is a recessive genetically heterogeneous disorder of motile cilia with chronic otosinopulmonary disease and organ laterality defects in ∼50% of cases. The prevalence of PCD is difficult to determine. Recent diagnostic advances through measurement of nasal nitric oxide and genetic testing has allowed rigorous diagnoses and determination of a robust clinical phenotype, which includes neonatal respiratory distress, daily nasal congestion, and wet cough starting early in life, along with organ laterality defects. There is early onset of lung disease in PCD with abnormal airflow mechanics and radiographic abnormalities detected in infancy and early childhood.

Keywords: Genetic testing; Kartagener syndrome; Nasal nitric oxide; Primary ciliary dyskinesia.

Figure 1

Ciliary ultrastructure. (A) Schematic of cross-section of cilium with 9 + 2 configuration. Ciliary ultrastructure by electron micrographs (EMs) from (B) normal subject and (C-G) patients with primary ciliary dyskinesia (PCD). (A) The 9 + 2 structure is shown with individual components of the axonemal structure. (B) Normal EM. (C) ODA defect, as seen in DNAH5 mutations. (D) ODA + IDA defect, as seen in DNAAF1 mutations. (E-F) IDA defect alone, and IDA defect with microtubular disorganization, as seen in CCDC39 mutations. (G) Missing central pair, as seen in ~12% of cilia with RSPH1 mutations.