F2 and acquired prothrombin deficiency: Lupus anticoagulant-hypoprothrombinemia syndrome (LAHPS) is a rare acquired bleeding disorder characterized by the presence of lupus anticoagulant (LA) and acquired hypoprothrombinemia caused by antiprothrombin (aPT) or antiphosphatidylserine/prothrombin (aPS/PT) complex antibodies [1].