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.

Keywords: GATA1, Down syndrome, Transient myeloproliferative disorder