[Relapsed acute myeloid leukemia with Down syndrome showing long disease-free survival after bone marrow transplantation].

We report a sixteen-year-old boy with Down syndrome and relapse of AML (M7), who has been in complete remission (CR) more than 12 months after bone marrow transplantation (BMT) from an HLA-matched sibling donor. Because monosomy 7 was detected at onset of AML and he experienced relapse after the treatment of AML 99 Down protocol, his prognosis was considered very poor. However, he achieved CR following chemotherapy that included high-dose AraC and BMT from an HLA-matched sibling donor without severe complication. He has remained in CR for more than 12 months after BMT. In this case, GATA1 mutation was not detected at either onset or relapse of AML and it is suggested that this case is in a different risk group than the usual Down syndrome patient with AML showing GATA1 mutation.