Antiphospholipid Antibody Syndrome

What Is It?

Antiphospholipid antibody syndrome (APS) is a condition defined by the presence of abnormal antibodies and a tendency to form blood clots or to have miscarriages.

People with antiphospholipid antibody syndrome produce antibodies that interact with certain proteins in the blood. This causes the blood to clot more than normal. The most commonly measured antiphospholipid antibodies include lupus anticoagulant and antibodies to cardiolipin or beta-2 glycoprotein.

The blood clots often form in the leg veins. The clots also can form in arteries. The blood clots may occur in any organ, but they tend to favor the lungs, brain, kidneys, heart and skin.

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