- SF3B1 mutation or, in the absence of SF3B1 mutation, no history of recent cytotoxic or growth factor therapy that could explain the myelodysplastic/myelo-proliferative features- no rearrangement of PDGFRA, PDGFRB, PCM1-JAK2, and FGFR1 (must be specifically excluded in cases of eosinophilia)and- no t(3;3)(q21.3;q26.2),inv(3)(q21.3;q26.2), or del(5q). This evidence concerns the gene JAK2 and Increased total eosinophil count.