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Stroke Health Center

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Antiphospholipid Syndrome

It is possible that the main title of the report Antiphospholipid Syndrome 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.


  • antiphospholipid antibody syndrome
  • APLS
  • APS
  • Hughes syndrome
  • lupus anticoagulant syndrome
  • PAPS
  • primary antiphospholipid syndrome

Disorder Subdivisions

  • CAPS
  • catastrophic antiphospholipid syndrome (Asherson's syndrome)

General Discussion

Antiphospholipid syndrome (APS) is a rare autoimmune disorder characterized by recurring blood clots (thromboses). Blood clots can form in any blood vessel of the body. The specific symptoms and severity of APS vary greatly from case to case depending upon the exact location of a blood clot and the organ system affected. APS may occur as an isolated disorder (primary antiphospholipid syndrome) or may occur along with another autoimmune disorder such as systemic lupus erythematosus (secondary antiphospholipid syndrome).

APS is characterized by the presence of antiphospholipid antibodies in the body. Antibodies are specialized proteins produced by the body's immune system to fight infection. In individuals with APS, certain antibodies mistakenly attack healthy tissue. In APS, antibodies mistakenly attack certain proteins that bind to phospholipids, which are fat molecules that are involved in the proper function of cell membranes. Phospholipids are found throughout the body. The reason these antibodies attack these proteins and the process by which they cause blood clots to form is not known.


Lupus Foundation of America, Inc.
2000 L Street NW
Suite 710
Washington, DC 20036
Tel: (202)349-1155
Fax: (202)349-1156
Tel: (800)558-0121

National Stroke Association
9707 E. Easter Lane
Suite B
Centennial, CO 80112
Tel: (303)649-9299
Fax: (303)649-1328
Tel: (800)787-6537

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

Madisons Foundation
PO Box 241956
Los Angeles, CA 90024
Tel: (310)264-0826
Fax: (310)264-4766

Autoimmune Information Network, Inc.
PO Box 4121
Brick, NJ 08723
Fax: (732)543-7285

APS Foundation of America
PO Box 801
La Crosse, WI 54602-0801
Tel: (608)782-2626
Fax: (608)782-6569

National Blood Clot Alliance
120 White Plains Road
Suite 100
Tarrytown, NY 10591
Tel: (914)220-5040
Tel: (877)466-2568

Hughes Syndrome Foundation
Conybeare House
Guy's Hospital
London, SE1 9RT
United Kingdom
Tel: 02071888217

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: 12/8/2011
Copyright 1994, 1995, 1996, 2001, 2002, 2007, 2011 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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