Ciliary Dysfunction

Primary ciliary dysfunction (PCD), first described in 1976, is a disorder of the structure and function of motile cilia that results in chronic oto-sinopulmonary disease. Cilia are hair-like structures that exist on the surface of cells. Motile cilia exist throughout the upper and lower respiratory tract, with each respiratory epithelial cell containing hundreds of cilia. Clearance of the airway and movement of respiratory secretions depends on the cilia beating in a coordinated fashion. PCD is a heterogeneous genetic condition that causes various abnormalities in the axonemal structures that comprise the cilia. This subsequently results in abnormal cilia structure and function.  This abnormal function impairs the ability of cilia to function in a coordinated manner, impairing mucociliary clearance and causing chronic upper and lower respiratory inflammation. Primary ciliary dysfunction typically presents with neonatal respiratory distress, early-onset year-round cough, nasal congestion, and laterality defect (situs inversus). Primary ciliary dysfunction diagnosis is challenging, given the lack of a single diagnostic test and the many conditions resulting in similar symptoms. Kartagener syndrome, which occurs in about 50% of PCD patients, is a triad of chronic sinusitis, bronchiectasis, and situs inversus resulting from embryonic (nodal) ciliary dyskinesia.