The order of acquisition influences clinical presentation as it has been demonstrated for ET and PV: mutations in either DNMT3A or TET2 are associated with an ET phenotype when acquired prior to JAK2 V617F; by contrast, acquisition of JAK2 V617F prior to mutation of DNMT3A or TET2 is associated with PV [42,43]. The gene discussed is TET2; the disease is acquired polycythemia vera.