The most common causes of the breakthrough PE are subtherapeutic anticoagulation (incorrect dose, drug interaction, or poor adherence) or underlying disease that can cause hypercoagulability such as active cancer,37 vasculitis (Behcet disease),38 myeloproliferative neoplasms,39 heparin-induced thrombocytopenia,40 vascular malformation,41 antiphospholipid antibody syndrome,42 and JAK2 V617F mutation.31,43. The gene discussed is JAK2; the disease is vascular malformation.