Gene mutations in myeloid neoplasms affect a number of cellular pathways, including epigenetic modification (ASXL1, DNMT3A, EZH2, IDH1, IDH2, TET2), RNA splicing (SF3B1, SRSF2, U2AF1, ZRSR2), transcriptional regulation (CEBPA, ETV6, PHF6, RUNX1, TP53, WT1), and proliferative signaling pathways (FLT3, JAK2, KRAS, NRAS). The gene discussed is JAK2; the disease is myeloid neoplasm.