Myeloid neoplasms with prominent eosinophilia often have rearrangements in the platelet-derived growth factor receptor <i>α</i> (<i>PDGFRA</i>) or <i>β</i> (<i>PDGFRB)</i> or are associated with core-binding factor AML. The gene discussed is PDGFRA; the disease is Increased total eosinophil count.