The cytosolic chaperone Poly(rC)-binding protein 1 (PCBP1) delivers iron to ferritin (Leidgens et al., 2013; Ryu et al., 2017) with evidence from Pcbp1 knockout mice, with microcytosis and anemia, that iron delivery to ferritin is required for normal erythropoiesis (Ryu et al., 2017). The gene discussed is PCBP1; the disease is anemia.