Yip et al. recently demonstrated that bone marrow (BM) progenitor cells from MDS patients with an endogenous U2AF1 S34F mutation showed aberrantly spliced H2AFY, resulting in reduced macroH2A1.1, but not macroH2A1.2, isoform expression in both erythroid and granulomonocytic derived colonies [6]. The gene discussed is MACROH2A1; the disease is myelodysplastic syndrome.