DDIT3 knockdown in patient 13 (RNA levels after knockdown shown in Fig. S6d), a male with MDS-MLD and anemia (hemoglobin (Hb) 11.8 g/dL), led to an increase in the percentage of cells in stage IV (CD235+ CD71-) at day 7 of differentiation, an effect that was increased at day 13, where cells expressing the control shRNA were partially blocked at stage III (Fig. 6b, c). The gene discussed is TFRC; the disease is metachromatic leukodystrophy.