Antiphospholipid syndrome occurs when immune system mistakenly attacks some of the normal proteins in r blood. Antiphospholipid syndrome can cause blood clots to form within arteries or veins. Antiphospholipid syndrome may cause blood clots to form in leg veins, a condition known as deep vein thrombosis (DVT).
Signs and symptoms of antiphospholipid syndrome may include: Blood clots in legs (deep vein thrombosis, or DVT) that may travel to lungs (pulmonary embolism), Repeated miscarriages or stillbirths and other complications of pregnancy, such as premature delivery and high blood pressure during pregnancy (preeclampsia), Stroke, Blood clots in the arteries of arms or legs (peripheral arterial thrombosis).
In antiphospholipid syndrome, body mistakenly produces antibodies against proteins that bind phospholipids, a type of fat present in blood that plays a key role in clotting (coagulation). Antibodies are specialized proteins that normally attack body invaders, such as viruses and bacteria. When antibodies attack phospholipid-binding proteins, blood may clot abnormally.