Although MCPIP1 deficiency did not affect erythropoiesis per se, the erythropoiesis in MCPIP1-/- bone marrow erythroblasts was significantly attenuated due to iron and vitamin B12 (VB12) deficiency, which was mainly resulted from autoimmunity-associated gastritis and parietal cell loss. The gene discussed is ZC3H12A; the disease is hyperinsulinemic hypoglycemia, familial, 4.