Update in Primary Ciliary Dyskinesia

Abstract

In Brief The spectrum of ciliary disease has widened from a primary upper and lower respiratory tract problem with the appreciation of the key role of sensory cilia. Five disease causing mutations have been discovered, but given the complexity of cilia, many more are likely to be found in the future. Primary ciliary dyskinesia may present with upper or lower airway disease, or be diagnosed after the discovery of associated conditions such as heterotaxy, complex congenital heart disease, and severe esophageal disease. Screening tests include nasal nitric oxide and in vivo measurements of mucociliary transport. Definitive diagnosis is by ciliary biopsy with measurement of ciliary beat frequency and pattern, followed by electron microscopy. Ciliary culture may help distinguish primary ciliary dyskinesia from ciliary abnormalities secondary to infection. Increasingly, genetic testing is becoming available. Once diagnosed, the severity is assessed, and follow-up should be in clinics with expertise in all areas of the condition. The evidence base for current treatment is weak, with no randomized controlled trials; all therapies are directed at complications, not the underlying abnormality. Lower airway disease is treated with airway clearance, antibiotics, and encouragement of exercise. A conservative approach to chronic secretory otitis media is advised. Although in many cases the patient is stabilized by medical therapy, some will go on to lung transplantation. In the future, specific therapies to reverse the ciliary dysfunction may become available. This article reviews recent advances in the genetics of primary ciliary dyskinesia and discuss the expanding spectrum of ciliopathy. We discuss the state of the art diagnostic tests, and review the age-related presentations. Finally, we discuss the management of the condition.