Korean J Hematol.  2008 Jun;43(2):118-121. 10.5045/kjh.2008.43.2.118.

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

• Choung HS
• Kim HJ
• Jung CW
• Kim SH

• KMID: 2252205
• DOI: http://doi.org/10.5045/kjh.2008.43.2.118

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.

Keyword

X-linked sideroblastic anemia; ALAS2; Mutation; R170H; Korea

MeSH Terms

Age of Onset
Anemia, Hypochromic
Anemia, Sideroblastic
Bone Marrow
Erythropoiesis
Exons
Genetic Diseases, Inborn
Genetic Diseases, X-Linked
Humans
Korea
Male
Pyridoxine
Sequence Analysis, DNA
Young Adult
Anemia, Sideroblastic
Genetic Diseases, X-Linked
Pyridoxine

Figure

• 

  Fig. 1 (A) Peripheral blood smear of the patient showed microcytic hypochromic anemia with dimorphism and anisopoikilocytosis (Wright-Giemsa stain, ×400). (B) The bone marrow aspirate smear showed mild erythroid dysplasia such as internuclear bridging (Wright-Giemsa stain, ×1,000). (C) Ringed sideroblasts were frequently observed (arrow) and were counted up to 30∼40% of normoblasts on bone marrow aspirate smear (Prussian blue stain, ×1,000).

• 

  Fig. 2 Direct sequencing of the ALAS2 gene detected a hemizygous c.509G＞A mutation (red box) in exon 5, which was predicted to substitute the highly conserved arginine residue at codon 170 with histidine (p.R170H).

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