antiphospholipid syndrome

antiphospholipid syndrome An immune disorder characterized by the presence of abnormal antibodies in the blood that are directed against the chemical structure of fats that contain phosphorus (phospholipids). Abbreviated APS. APS is associated with abnormal blood clotting, migraine headaches, recurrent pregnancy loss, and low blood platelet counts (thrombocytopenia). APS can occur by itself (primary APS) or be caused by an underlying condition (secondary APS), such as systemic lupus erythematosus. Examples of antiphospholipid antibodies are cardiolipin antibody and lupus anticoagulant. See also annexin V.