Mutations of SF3B1, a splicing complex component, may, via altered gene expression or abnormal protein-protein interaction, disturb mitochondrial iron handling in a way that causes mitochondrial iron accumulation in acquired sideroblastic anemia. Possible targets include (1) the final step of heme synthesis, that is, incorporation of Fe2⁺ into protoporphyrin IX by ferrochelatase; (2) the mitochondrial respiratory chain (RC), whose malfunction may lead to oxidation of Fe2⁺ (with Fe3⁺ being rejected by ferrochelatase); (3) iron sulfur cluster (ISC) assembly, whose malfunction can impair the RC as well as ferrochelatase; and (4) the export of heme or ISCs from the mitochondrial matrix.