The peripheral blood and bone marrow of moribund Fancc-/-;Mad2+/- mice contained large myeloid cells with increased nucleus-to-cytoplasm ratio, irregular nuclei, and open chromatin (Figures 1N, O), similar to the AML/MDS seen in aging Fancc-/- mice (8). The gene discussed is MAD2L1; the disease is acute myeloid leukemia.