Antiphospholipid syndrome is best described as:

• A. An acquired thrombotic condition often seen with autoimmune disorders, particularly SLE
• B. An inherited platelet deficiency
• C. A bacterial infection that affects the blood vessels
• D. A coagulation disorder causing excessive bleeding

Answer: (A)

Antiphospholipid syndrome is an acquired hypercoagulable autoimmune condition driven by antibodies against phospholipid-binding proteins, such as lupus anticoagulant, anticardiolipin, and anti-β2-glycoprotein I. These antibodies increase the risk of arterial and venous thrombosis and can cause pregnancy-related complications. It is most commonly seen in people with autoimmune diseases, particularly systemic lupus erythematosus, and it promotes clotting rather than bleeding, distinguishing it from inherited bleeding disorders or infections. Lab findings may show a prolonged aPTT that does not correct with mixing studies, reflecting the presence of antiphospholipid antibodies rather than a true bleeding tendency.