Primary ciliary dyskinesia (PCD), also known as immotile cilia syndrome, is a genetically heterogeneous group of disorders with autosomal recessive inheritance that are characterized by defective ciliary motion or absent cilia. This can be present in the respiratory tract, nasal and paranasal sinuses, spermatozoa, and embryonic nodal cilia. Absent or impaired cilia function results in compromised mucociliary clearance, with various manifestations including chronic respiratory tract infections, heterotaxy, and male infertility.

Primary ciliary dyskinesia is evenly distributed between men and women and occurs in approximately 1 out of every 10 000-30 000 individuals. Due to involvement of embryonic nodal cilia, body symmetry is random and up to 50% of patients will have situs inversus totalis.

The symptoms and disease progression vary considerably based on the degree and distribution of ciliary dysfunction. Some patients' only manifestation will be infertility, while others can have progressive lung disease from bronchiectasis. Other manifestations include chronic rhinosinusitis with nasal polyps, chronic otitis with conductive hearing loss, and headaches. Approximately 12% of people with primary ciliary dyskinesia will have heterotaxy, with abnormalities in the position or structure of the gastrointestinal tract, spleen, or heart.