Although Abin1Q478H/Q478H cells are sensitive to RIPK1 kinase–RIPK3–MLKL‐dependent necroptosis, only anemia and splenomegaly are alleviated by RIPK3 deficiency but not by MLKL deficiency or the RIPK1 kinase‐dead mutation. The gene discussed is RIPK3; the disease is Splenomegaly.