Understanding Primary Ciliary Dyskinesia

A rare genetic condition affecting the function of cilia in various organs of the body

What is PCD?
Genetics
Symptoms
Diagnosis
Management
Resources

What are Cilia?

Cilia are microscopic, hair-like structures that line the airways (including the nose, sinuses, and lungs), middle ear, and reproductive tract. In healthy individuals, cilia beat in a coordinated manner to clear mucus and trapped particles from the airways, helping to prevent infection and maintain respiratory health.

PCD affects approximately 1 in 15,000-30,000 individuals, making it a rare genetic disorder.

Genetic Basis

PCD is caused by mutations in genes responsible for the structure and function of cilia. Currently, more than 40 genes have been identified that can cause PCD when mutated. The condition is inherited in an autosomal recessive pattern, meaning an individual must inherit affected copies of the gene from both parents to develop PCD.

Common PCD genes include DNAH5, DNAI1, CCDC39, and CCDC40, which affect different parts of the ciliary structure.

Clinical Manifestations

PCD affects multiple organ systems due to the widespread presence of cilia throughout the body. Common symptoms include:

  • Chronic respiratory infections starting in early childhood
  • Persistent nasal congestion and rhinitis
  • Chronic sinusitis
  • Recurrent middle ear infections
  • Bronchiectasis (permanent airway damage)
  • Approximately 50% of patients have situs inversus (organs on opposite side of body)
  • Male and female fertility issues

The combination of situs inversus, chronic sinusitis, and bronchiectasis is known as Kartagener syndrome, a subtype of PCD.

Diagnosis

Diagnosis of PCD typically involves multiple tests, as no single test can definitively diagnose all cases. Common diagnostic approaches include:

  • Nasal Nitric Oxide measurement (typically low in PCD)
  • High-speed video microscopy analysis of ciliary beat pattern
  • Transmission electron microscopy of ciliary ultrastructure
  • Genetic testing for known PCD mutations

Early diagnosis is important for implementing treatments that can help prevent long-term complications like bronchiectasis.

Management

While there is currently no cure for PCD, treatment focuses on preventing and managing symptoms through:

  • Regular airway clearance techniques
  • Prompt treatment of respiratory infections
  • Regular monitoring of lung function
  • ENT (ear, nose, and throat) care
  • Bronchodilators when indicated

With proper management, most people with PCD can lead full and active lives, though regular medical care is essential.

References

  1. Shapiro AJ, et al. Diagnosis, monitoring, and treatment of primary ciliary dyskinesia: PCD foundation consensus recommendations based on state of the art review. Pediatr Pulmonol. 2016;51(2):115-132.
  2. Horani A, Ferkol TW. Primary ciliary dyskinesia and associated sensory ciliopathies. J Allergy Clin Immunol. 2018;142(2):376-385.
  3. Knowles MR, et al. Primary ciliary dyskinesia: diagnosis and phenotypes. Am J Respir Crit Care Med. 2013;188(8):913-922.
  4. Werner C, et al. An international registry for primary ciliary dyskinesia. Eur Respir J. 2016;47(3):849-859.