A Japanese family with X-linked sideroblastic anemia affecting females and manifesting as macrocytic anemia.

X-linked sideroblastic anemia (XLSA) is a rare hereditary disorder that typically manifests in males as microcytic anemia. Here, we report a family with XLSA that affects females and manifests as macrocytic anemia. The proband was a Japanese woman harboring a heterozygous mutation c.679C>T in the ALAS2 gene. This mutation causes the amino acid substitution R227C, which disrupts the enzymatic activity of erythroid-specific δ-aminolevulinic acid synthase. The mutation was not detected in the ALAS2 complementary DNA from peripheral blood red blood cells of the proband, indicating that the cells were mostly derived from erythroblasts expressing wild-type ALAS2. The proband's mother, who had been diagnosed with myelodysplastic syndrome, also had XLSA with the same mutation. Clinicians should be aware that XLSA can occur not only in males but also in females, in whom it manifests as macrocytic anemia.