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Disease Profile

Swyer-James syndrome

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Swyer-James-MacLeod syndrome


Swyer-James syndrome is a rare condition in which the lung (or portion of the lung) does not grow normally and is slightly smaller than the opposite lung, usually following bronchiolitis in childhood. It is typically diagnosed after a chest X-ray or CT scan which shows unilateral pulmonary hyperlucency (one lung appearing less dense) and diminished pulmonary arteries.[1][2] Affected individuals may not have any symptoms, or more commonly, they may have recurrent pulmonary infections and common respiratory symptoms.[2] The cause of the condition is not completely understood.


Individuals with Swyer-James syndrome may not have any symptoms, but affected individuals can have chronic or recurring lung infections, shortness of breath (dyspnea) when performing an activity, coughing up of blood (hemoptysis), and even severe respiratory impairment.[2]


The cause of Swyer-James syndrome is not completely understood. Most experts agree that the initial abnormality occurs in the distal bronchi (air tubes that bring air to and from the lungs) after an infection during early childhood. The smaller size of the affected lung may be due to the infection inhibiting the normal growth of the lung. A number of reports have described Swyer-James syndrome following childhood histories including radiation therapy; measles; pertussis (whooping cough); tuberculosis; breathing in a foreign body; mycoplasma; and viral infections, especially adenovirus. Research has suggested that a hyper-immune reaction in the lung (producing an unusual abundance of antibodies) may play a role in sustaining airway damage after the initial infection. Some have argued a pre-existing lung abnormality may predispose individuals to the condition. Although bronchial damage of some kind during childhood is generally considered to play an important role, many affected individuals have had no known history of an airway infection. It is possible that some unknown factors present at birth may contribute to the development of Swyer-James syndrome.[2]


Individuals with Swyer-James syndrome reportedly have been treated conservatively in the past. However, although there are few reports published, it has been recognized that surgical treatment should be considered when infections cannot be controlled. There have been reports of affected individuals being treated with pneumonectomy (removal of a lung), lobectomy (removal of one or more lobes of a lung) or segmentectomy (removal of a specific segment).

It has been proposed that individuals with Swyer-James syndrome may benefit from lung volume reduction surgery (LVRS), a procedure in which damaged tissue is removed from the lung. LVRS was reportedly performed successfully in an individual with Swyer-James syndrome, and it has been suggested that the procedure could be used for managing the condition in other affected individuals because it has shown to be effective for improving pulmonary function and symptoms.[3]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Swyer-James syndrome. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles


  1. Beverly P Wood. Swyer-James Syndrome Imaging . eMedicine. May 25, 2011; https://emedicine.medscape.com/article/361906-overview#a19. Accessed 10/19/2011.
  2. Bai Chong, Song Xiao-lian, Shi Hui, Yao Xiao-Peng and Li Qiang. Swyer-James Syndrome with Peculiar Course and Ipsilateral Pulmonary Vein Defect. Internal Medicine. 2011; 50:1829-1833.
  3. Akira Tasaki, Ryoichi Nakanishi. Lung Volume Reduction Surgery for a Professional Athlete With Swyer-James Syndrome. The Annals of Thoracic Surgery. July 2005; 80(1):342-344.

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