Primary ciliary dyskinesia (PCD) is an autosomal recessive genetic condition in which the microscopic cells in the respiratory system called cilia do not function normally. Ciliary dysfunction prevents the clearance of mucous from the lungs, paranasal sinuses and ears. Bacteria and irritants in the mucous lead to frequent respiratory infections. Kartagener syndrome is a type of Primary ciliary dyskinesia associated with a mirror-image orientation of the heart and other internal organs.
Causes of Primary ciliary dyskinesia (PCD)
Primary ciliary dyskinesia usually follows autosomal recessive genetic inheritance. Recessive genetic disorders occur when an individual inherits the same abnormal gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms.
All individuals carry multiple abnormal genes for various traits. Parents who are close relatives have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.
The symptoms of primary ciliarydyskinesia vary greatly in affected individuals. Symptoms often begin shortly after birth and can include coughing, gagging, choking and lung collapse. Affected individuals often experience chronic sinus, middle ear and lung infections as well as chronic coughing, excess mucus and hearing loss. The recurring respiratory infections can lead to an irreversible scarring and obstruction in the bronchi and severe lung damage.
Cilia are also present in the ventricles of the brain and in the reproductive system so ciliary dysfunction can also affect other body systems. Affected men are often infertile because movement of sperm is abnormal. Primary ciliary dyskinesia may also be associated with infertility and ectopic pregnancy in females.
Diagnosis of Primary ciliary dyskinesia (PCD)
Primary ciliary dyskinesia is diagnosed definitively through examination of lung or sinus tissue obtained from a biopsy. Specific structural defects that are present in these tissues can be detected under an electron microscope. Early diagnosis is important in order to provide prophylactic treatment to prevent or decrease damage to the respiratory system from recurrent infections. Screening for levels of nasal nitric oxide is helpful to identify individuals who may have Primary ciliary dyskinesia and should proceed with a biopsy.
Airway clearance therapy is used to keep the lung tissue healthy for as long as possible. This therapy may include routine washing and suctioning of the sinus cavities and ear canals. Antibiotics, bronchodilators, steroids and mucus thinners are also used to treat Primary ciliary dyskinesia. Routine hearing evaluation is important for young children and speech therapy and hearing aids may appropriate for children with hearing loss and speech problems. Lung transplantation is an option for severe, advanced lung disease. Surgery may be indicated if heart defects are present.