kjh The Korean Journal of Hematology Korean J Hematol 1738-7949 2092-9129 Korean Society of Hematology 10.5045/kjh.2008.43.1.43 kjh-43-43 Case Report GATA1 Mutation in Transient Myeloproliferative Disorder of Down Syndrome HaJung SookM.D. 1 LeeWon MokM.D. 1 KimJi HyeM.D. 1 RyooNam HeeM.D. 1 JeonDong SukM.D. 1 KimJae RyongM.D. 1 KimHeung SikM.D. 2 ChoiByung KyuM.D. 2 Department of Laboratory Medicine, Deagu, Korea Department of Pediatrics, School of Medicine, Keimyung University, Deagu, Korea Correspondence to：Jung Sook Ha, M.D. Department of Laboratory Medicine, School of Medicine, Keimyung University 194, Dongsan-dong, Jung-gu, Daegu 700-712, Korea Tel: ＋82-53-250-7266, Fax: ＋82-53-250-7275 E-mail: ksksmom@dsmc.or.kr 32008 1932008 43143 47 06112008 04012008 10012008 Copyright © 2008 Korean Society of Hematology 2008 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Children with Down syndrome (DS) have a higher risk of developing leukemia than do healthy children, and they especially have a higher risk for developing transient myeloproliferative disorder (TMD) or acute megakaryocytic leukemia (AMKL). In recent studies, it has been reported that most of these patients have acquired mutation of the GATA1 gene, which encodes the erythroid/megakaryocytic transcription factor GATA1. GATA1 mutations have not been found in AMKL patients who did not have DS and other hematologic malignancies in DS. Most of the GATA1 mutations in DS-TMD/AMKL are nonsense mutations that are mainly located in exon 2. We observed a nonsense mutation in exon 2 of GATA1 [c.189_190delCA (Tyr63X)] in one case of DS-TMD. The GATA1 mutation has been thought to be an early event in the leukemogenesis of DS-TMD/AMKL and it could be used as a stable molecular marker to assess the treatment response or to monitor for the recurrence of DS-TMD/AMKL.

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Bone marrow aspiration smear showing increased immature cells which have less condensed coarse chromatin and cytoplasmic blebbing (Wright-Giemsa stain, ×1,000).

Direct sequence analysis of exon 2 of GATA1 gene. Wild-type (WT) trace is shown above the patient result for comparison. Note there are two superimposed sequence traces in patient result. Thesu-perimposed traces are wild type and mutant type which has deletion of CA (rectangular) from nucleotides 189 to 190 (c.189_190delCA). This mutation is a nonsense mutation that codon 63 TAC was changed to stop codon TAG.