Acquired prothrombotic disorders include the antiphospholipid syndrome, paroxysmal nocturnal haemoglobinuria, and MPNs: polycythaemia vera (PV), essential thrombocythaemia (ET), and idiopathic myelofibrosis.23 Recent reports confirm that the JAK2 V617F mutation is strongly implicated in the pathogenesis of myeloproliferative disorder that may be associated with increased rates of thrombosis.24,25. Here, JAK2 is linked to essential thrombocythemia.