What is PCD?
Primary ciliary dyskinesia is an umbrella term for inherited (genetic) disorders of microscopic, whip-like organelles (little organs) called cilia that line the upper and lower respiratory tract including nasal passages, sinuses and lung, and eustachian tubes of the ear, the reproductive organs, and the ventricles of the brain. The activity of motile (moving) cilia, working in cooperation with airway mucus, provides a first line of defense for the airways, maintaining healthy airway tissue. This important biological system is known as ‘mucociliary clearance.’ Defects of mucociliary clearance can lead to profound illness. Cystic fibrosis is an example of another devastating genetic disorder of mucociliary clearance that shares many features with PCD.
Ciliary activity is also responsible for organ placement in the developing embryo. When ciliary function is impaired, congenital defects of the structure and/or placement of internal organs may occur. Complete reversal of the organs, a condition called situs inversus totalis, occurs in approximately 50% of all PCD patients. Heterotaxy and situs ambiguus (‘ambiguous’), where organ laterality is interrupted, may also occur. Polysplenia (multiple spleens), asplenia (no spleen), congenital heart defects, vascular abnormalities and cystic lesions in the kidneys, spleen, liver or pancreas, may all be seen in PCD with heterotaxy/situs ambiguus.
In PCD, impaired ciliary activity results in lifelong respiratory disease with chronic, debilitating infections of the lungs, sinuses and ears. Over time, chronic infection results in permanent damage to these areas and, in the case of the lungs, possible respiratory failure. Adults with PCD experience infertility (most males) or sub-fertility (some females). Chronic sinus and ear disease, including hearing loss, are common in PCD.
The video below shows the comparison of normal cilia versus PCD cilia caused by mutations in a gene called DNAh5. It is important to note that not all cases of PCD have such a strikingly abnormal beat pattern. Diagnosis of PCD relies on assessment of ultrastructural abnormalities–not ciliary beat:
Normal Cilia vs. Impaired Cilia (PCD)
Common Features
- Neonatal respiratory problems, in rare instances resulting in infant death
- Organ placement/structural abnormalities
- Chronic cough, usually present from birth or early infancy
- Excessive production of mucus and recurrent, debilitating lung infections
- Bronchiectasis, which presents as scarring or permanent damage to the airways
- Sinusitus, often severe and from an early age
- Frequent and severe ear congestion/infections, resulting in conductive hearing loss in children
- Neurogenic hearing loss may occur in adults
- Male infertility, female sub-fertility or ectopic pregnancy
Disease Management
There is no cure for PCD. Management is focused on symptom relief and slowing the progression of lung damage. Daily interventions include airway clearance and aggressive treatment of respiratory inflammation and infection in the upper and lower respiratory tract. More strenuous intervention is required for disease exacerbations (flare ups). The use of IV or inhaled antibiotics and supplemental oxygen may be required for acute symptoms. Repeated hospitalizations are common in PCD. For more information about disease management, visit Living with PCD.
Long-Term Outlook
People with PCD are sick from birth and experience a greatly diminished quality of life. Disease expression is variable with some succumbing to lung damage early in life. Others may live into the fifth, sixth, or even seventh decade, but the disorder is progressive and quality of life issues result in a lifespan that is far from ‘normal.’
Recognizing the urgent need for better diagnostic capability and improved access to research and care for individuals with PCD, the PCD Foundation, in collaboration with our research partners, established a PCD Clinical Center Network. This North American initiative provides patients and healthcare providers with state-of-the-art diagnostic and treatment options, while creating a path to clinical trials that will ultimately help us find a cure for PCD. Click here to learn more about the clinical center network.
Consensus Statement
In 2015, PCD experts from North America, including top pulmonologists, medical professionals, and PCDF representatives published recommendations for diagnosis, monitoring, and treatment of primary ciliary dyskinesia. This consensus statement represents the best evidence currently available from expert physicians and researchers with years of experience diagnosing and treating PCD. It will be periodically updated as the evidence directs. Please feel free to download the PCDF Consensus Recommendations and share with your own physicians.