Genetic testing excluded acute myeloid leukemia, myeloproliferative neoplasms, myelodysplastic syndromes, systemic mastocytosis, and myeloid/lymphoid neoplasms with eosinophilia, as results for PDGFRA, PDGFRB, FGFR1, or PCM1-JAK2 rearrangements were negative. The gene discussed is FGFR1; the disease is myeloproliferative disorder.