Information on the following diseases can be found in the Related Disorders section of this report:

• cystic fibrosis
• IgG subclass deficiency
• gastroesophageal reflux
• Wegener’s granulomatosis

The symptoms of primary ciliary dyskinesia vary greatly in affected individuals. Symptoms often begin shortly after birth and can include coughing, gagging, choking and lung collapse (neonatal respiratory distress). 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 (bronchiectasis) 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 (motility) is abnormal. PCD may also be associated with infertility and ectopic pregnancy in females.

Movement of cilia may also be important in organ placement in the developing embryo. Approximately 50% of individuals with PCD have Kartagener syndrome in which the internal organs including the heart, liver, spleen and intestine are on the opposite side of the body (situs inversus totalis). Some individuals with PCD have a condition called heterotaxy (situs ambiguus) in which internal organs are abnormally positioned and have abnormal structure. Approximately, half of the PCD patients with heterotaxy have congenital heart defects that can be serious and life threatening.

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. The risk for two carrier parents to both pass the defective gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier like the parents is 50% with each pregnancy. The chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%. The risk is the same for males and females.

All individuals carry 4-5 abnormal genes. Parents who are close relatives (consanguineous) 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.

Primary ciliary dyskinesia occurs in approximately 1 in 16,000 to 20,000 births. That translates to the incidence of Kartagener syndrome as 1 in 32,0000 to 40,000 births.

Symptoms of the following disorders can be similar to those of primary ciliary dyskinesia. Comparisons may be useful for a differential diagnosis:

Cystic fibrosis is a genetic disease that affects approximately 30,000 children and adults in the United States. Because of a defective gene, mucus-secreting glands within the lining of the lung's airways (bronchi) produce unusually thick, sticky secretions. This clogs the air passages, promotes bacterial growth, and leads to chronic obstruction, inflammation, and infection of the airways. These thick secretions also obstruct the pancreas, keeping digestive enzymes from reaching the intestines to help break down and absorb food. In many cases, this disorder is apparent soon after birth, but 10% of the people with cystic fibrosis do not receive a diagnosis until age 18 or older. (For more information on this disorder, choose "cystic fibrosis" as your search term in the Rare Disease Database.)

IgG subclass deficiency is characterized by recurrent infections of the ears, sinuses, bronchi and lungs. IgG is a class of antibodies that contains four different types of IgG molecules. Individuals who are missing or have low levels of one or two of these types are at risk for respiratory infections.

Wegener's granulomatosis is a rare disorder characterized by inflammation of blood vessels (vasculitis) that results in damage to various organ systems of the body, most often the respiratory tract and kidneys. Symptoms may include ulcerations of the mucous membranes in the nose with secondary bacterial infection, a persistent runny nose, sinus pain, and chronic middle ear infection (otitis media) potentially resulting in hearing loss. In some cases, kidney abnormalities may progress to kidney failure, a serious complication. If the lungs are affected, a cough, expectoration of blood (hemoptysis), and inflammation of the thin membrane lining the outside of the lungs and the inside of the lung may be present. The exact cause of Wegener's granulomatosis is not known. (For more information on this disorder, choose "Wegener's" as your search term in the Rare Disease Database.)

Gastroesophageal reflux (GERD) is a digestive disorder characterized by the passage or flowing back (reflux) of the contents of the stomach or small intestines (duodenum) into the esophagus. The esophagus is the tube that carries food from the mouth to the stomach. Symptoms of gastroesophageal reflux may include a sensation of warmth or burning rising up to the neck area (heartburn or pyrosis), swallowing difficulties (dysphagia), and chest pain. This condition is a common problem and may be a symptom of other gastrointestinal disorders. (For more information on this disorder, choose "GERD" as your search term in the Rare Disease Database.)

Diagnosis
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. Research is underway to develop a screening test for nasal nitric oxide that would help to identify individuals who may have PCD and should proceed with a biopsy. Research to develop testing for genes responsible for PCD is also underway. Two genes are associated with PCD (DNAI1 and DNAH5) and together account for approximately 38% of cases. Molecular genetic testing for by full gene sequencing is is currently available on a research basis only. Clinical molecular genetics testing for limited number of mutations at Molecular Genetics Laboratory at University of North Carolina at Chapel Hill and at Ambry Genetics.

Treatment
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 (mucolytics) are also used to treat PCD. 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.

The Genetic Disorders of Mucociliary Clearance Consortium is a network of four U.S. centers (University of North Carolina at Chapel Hill, Washington University in St. Louis, University of Washington and University of Colorado) that are collaborating in the diagnostic testing, genetic studies and clinical trials in patients with disorders of mucociliary clearance including primary ciliary dyskinesia. Contacts for this consortium are as follows:

Beth Godwin
Administrative Assistant
Cystic Fibrosis/Pulmonary Research & Treatment Center
7019 Thurston Bowles Bldg.
CB#7248
Chapel Hill, NC 27599-7248 \

FAX: 919-966-7524
Email: godwine@med.unc.edu
Susan Minnix, RN, BSN
Research Coordinator
4007 Thurston Bowles Bldg.
CB#7248
Chapel Hill, NC 27599-7248

FAX: 919-843-5309
Email: sminnix@med.unc.edu

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com

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