A well-recognized candidate gene for MDS with the RS phenotype is the iron transporter ABCB7. Our group first reported marked downregulation of ABCB7 in MDS patients with RARS subtype.11 Hereditary X-linked sideroblastic anemia with ataxia is caused by partial loss-of-function mutations of ABCB7, which inhibit heme biosynthesis.12 Moreover, knockdown of ABCB7 in HeLa cells resulted in an iron-deficient phenotype with mitochondrial iron accumulation.13 Conditional gene targeting in mice has shown that ABCB7 is essential for hematopoiesis.12 This evidence concerns the gene ABCB7 and myelodysplastic syndrome with ring sideroblasts.