Identification of a Hemizygous R170H Mutation in the ALAS2 Gene in a Young Male Patient with X-linked Sideroblastic Anemia

ABSTRACT

X-linked sideroblastic anemia (XLSA) is a rare hereditary disease characterized by microcytic hypochromic anemia, ineffective erythropoiesis and the presence of numerous ringed sideroblasts in the bone marrow. The causative gene is the erythroid delta-aminolaevulinate synthase 2 gene (ALAS2) on Xp11.21. We report here a case of XLSA. The patient was a 20-year-old Korean man referred to our hospital under the impression of sideroblastic anemia (SA). Laboratory findings, including a peripheral blood smearand bone marrow study, were compatible with SA. The family history was not remarkable. Based on the early age of onset, we suspected a hereditary form of SA, particularly XLSA. Direct DNA sequencing of ALAS2 detected a hemizygous c.509G>A (R170H) mutation in exon 5 of the gene. The patient showed minimal response to pyridoxine treatment. To the best of our knowledge, this is the first case of genetically confirmed XLSA from a mutation in ALAS2 in Korea.