Primary ciliary dyskinesia is a recessively inherited group of heterogeneous disorders that result from a primary defect in the structure or function of cilia resulting in altered mucociliary transport in the respiratory tract and defective mucociliary clearance. Several structural abnormalities such as dynein arms defects, radial spoke defects or peripheral microtubules transposition have been described. These abnormalities predominantly affect the lungs, sinuses and ears. In the lungs and sinuses, ineffective clearance causes the retention of mucus and bacteria within the respiratory tract, and the development of respiratory infections and chronic inflammation.

The symptoms of primary ciliary dyskinesia are present from birth, but there is a significant variation in both the severity of symptoms and the age at which the condition is diagnosed. Signs begin in the infant with recurrent sinopulmonary infections (chronic cough with bronchorrhea, chronic rhinosinusitis or chronic secretory otitis media). The lungs, nose, middle ear and sinuses are primarily affected as they rely on the coordinated, effective beating of cilia to remove secretions. In addition, ciliary defects affect flagella of spermatozoa, causing infertility in males. Infertility is one of the situations where the disease is diagnosed in males, but also in females in whom the risk of ectopic pregnancy is increased. About 50% of all patients affected with primary ciliary dyskinesia have laterality defects such as situs inversus totalis (Kartagener's syndrome) wherein there is a mirror image reversal of all visceral organs. The classic Kartagener syndrome, characterized by the triad of situs inversus, chronic inflammation, and bronchiectasis, is shown only by a subset of patients with PCD. About 50% of male patients with PCD turn out to be infertile, most likely due to defects in the sperm tails. The disease is not common and has an incidence of approximately 1:15,000 to 1:30,000 live births.

If untreated, PCD can lead to bronchiectasis, or a permanent dilatation of the bronchial tree, with chronic respiratory failure in 1/3 of cases. Recurrent ear infections are another feature of the condition, and may lead to transient or irreversible hearing loss.

The prognosis of the disease depends on the severity of the respiratory involvement. There is no aetiological treatment of primary ciliary dyskinesia, but when diagnosed early, management can be optimized. A diagnosis of PCD is suspected based on the clinical picture of patients. However, a confirmation requires the demonstration of ciliary structural abnormalities as seen by electron microscopy, the evidence of abnormal ciliary function, or mutations in one of the two genes known and recognized to cause the condition. Treatment is focused on initially clearing the mucus via chest percussion and breathing maneuvers, and chest and ear infection through the use of antibiotics. Extensive infections may require sinus surgery. Routine immunizations are important to prevent secondary infections. Hearing aids may be necessary for patients with hearing problems.