Philadelphia chromosome-positive acute lymphoblastic leukemia and Down syndrome.

Children with Down syndrome (DS) are at high risk of developing acute lymphoblastic leukemia (ALL), but Philadelphia chromosome-positive (Ph+) ALL is rare in DS children. We report a case of Ph+ALL with DS complicated by chronic heart failure. Complete molecular remission was obtained after imatinib-combined chemotherapy, although infectious episodes during the neutropenic period worsened the heart condition. After two courses of intensification chemotherapy, the patient underwent reduced intensity stem cell transplantation from an HLA-identical sibling donor followed by post-transplant imatinib. The patient maintained molecular complete remission for >2 years. This case report is the first description of the safe and effective use of imatinib for DS-Ph+ALL. This case suggests the potential of molecular targeting therapy in DS-ALL, which is often complicated by congenital diseases, and the importance of treating DS-ALL while maintaining intensity and reducing treatment-related toxicity.