In our study, the fatal myelomonocytic leukemia that developed in TAK1ΔM mice was not reversed by the simultaneous deletion of TNFR1; in fact, TNFR1-null TAK1ΔM mice developed splenomegaly and died at 25 to 43 weeks of age. The gene discussed is TNFRSF1A; the disease is Splenomegaly.