(1) Background: Antiphospholipid syndrome (APS) is associated with thrombotic events and the laboratory identification of antiphospholipid antibodies (aPL), in which lupus anticoagulant (LA), anticardiolipin (aCL), and anti-β2 glycoprotein I antibodies are included. The gene discussed is FASLG; the disease is autoimmune polyendocrinopathy.