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Pulmonary Alveolar Proteinosis

It is possible that the main title of the report Pulmonary Alveolar Proteinosis is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • PAP
  • Alveolar Lipoproteinosis Phospholipidosis

Disorder Subdivisions

  • None

General Discussion

The lung is composed of millions of tiny air sacs (alveoli) with very thin walls that allow oxygen in the air we breathe to pass through into the blood. Surfactant is a natural substance consisting of fat (mostly phospholipids) and a small amount of protein made in alveoli. Normally, a thin layer of surfactant present on the surface of alveoli helps them stay open. This allows air to come in and out as we breathe. Once used, surfactant is removed (cleared) from alveoli by cells called alveolar macrophages. This helps prevent surfactant from building up too much. Alveolar macrophages require a protein called granulocyte/macrophage-colony stimulating factor (GM-CSF) to maintain a normal surfactant level in alveoli (a process called surfactant homeostasis).

Pulmonary alveolar proteinosis (PAP) is a syndrome, a set of symptoms and signs and not just a single disease, in which surfactant slowly builds up in alveoli. This blocks air from entering alveoli and oxygen from passing through into the blood, which results in a feeling of breathlessness (dyspnea). Research has greatly improved our understanding of the diseases that cause PAP and how to identify (diagnose) and treat them. Diseases that cause PAP can occur in men, women, and children of all ages, ethnic backgrounds, and geographic locations. Disease severity varies from mild to severe and depends on which disease is present. Thus, it is important to know which disease is causing PAP in order to determine the best therapy and expected treatment response. Diseases that cause PAP can be grouped into three categories: primary PAP, secondary PAP, and congenital PAP (more accurately called disorders of surfactant production).


American Lung Association
1301 Pennsylvania Ave NW
Suite 800
Washington, DC 20004
Tel: (202)785-3355
Fax: (202)452-1805
Tel: (800)586-4872

NIH/National Heart, Lung and Blood Institute
P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

British Paediatric Orphan Lung Disease

Rare Diseases Clinical Research Network
University of South Florida, Pediatrics Epidemiology Center
3650 Spectrum Boulevard, Suite 100
Tampa, FL 33612
Tel: (813)396-9501
Fax: (813)910-5997
Tel: (866)533-9104

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated: 9/10/2014
Copyright 1988, 1989, 1993, 1997, 2004, 2014 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: May 28, 2015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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