Primary Ciliary Dyskinesia.

Primary ciliary dyskinesia (PCD) is a rare but underdiagnosed disorder that affects motile cilia function throughout the body. With increasing prevalence through ongoing genetic discovery, PCD underlies the disease process in a significant number of patients with chronic suppurative lung disease and bronchiectasis when properly investigated using current diagnostic standards. Classic PCD symptoms include chronic rhinosinusitis and otitis, organ laterality defects, infertility, year-round productive cough, and recurrent pneumonias with bronchiectasis. Clinical symptoms of PCD manifest very early in life (often at birth), although diagnosis frequently is delayed because of poor phenotypic recognition and limited access to specialized diagnostic testing. In the past decade, PCD research networks have established specific PCD phenotypes to increase clinical recognition, and the availability of PCD genetic panels in various commercial laboratories has expanded access to an accurate PCD diagnosis greatly. Clinical practice guidelines also were created to guide diagnosis and management of this rare but increasingly recognized suppurative respiratory disease. PCD is more common than previously thought and can be recognized through specific clinical phenotypes in both children and adults. Diagnostic PCD testing outside of highly specialized centers can be difficult, but increased availability of nasal nitric oxide measurement and commercial genetic panels now allows for noninvasive screening and definitive diagnosis regardless of center expertise. Identification of patients with accurately diagnosed PCD is needed worldwide to populate future clinical trials and to develop disease-specific therapies for PCD.