To further complicate the clinical diagnosis and management of APS, some patients have clearing antibodies against prothrombin, which affects the baseline prothrombin time (PT) and international normalised ratio (INR), with affected patients having a possible risk of bleeding; this condition is termed “Lupus anticoagulant-hypoprothrombinemia syndrome” by some workers in the field [62]. Here, F2 is linked to autoimmune polyendocrinopathy.