Constitutional Pericentric Inversion of Chromosome 9 inv (9) in Pediatric Leukemia and Stem Cell Transplantation / 대한소아혈액종양학회지

ABSTRACT

PURPOSE: Pericentric inv (9) occurs in about 0.8~2% of the normal population. The implication of inv (9) in hematological malignancies and/or in stem cell transplantation (SCT) has not been thoroughly elucidated. METHODS: To further delineate the characteristics, we describe our experiences of inv (9) in 2 patients who underwent SCTs and 1 patient with ALL. RESULTS: Case 1. An 11-year-old girl with AML M2 showed 46, XX, inv (9). After remission, her consolidation cycles were associated with slow platelet recovery. She underwent autologous BMT, however, the engraftment was rather slow, and relapsed at 7 months. 2nd remission was achieved after prolonged cytopenia. She underwent reduced intensity unrelated cord blood transplant. Her posttransplant course was uneventful with ANC & gt; 500/microL at D+18 and platelet > 50 k/microL at D+38. Karyotyping showed 46, XY. She is now well at 16 months after 2nd transplant. Case 2. A 10-year-old girl presented with severe aplastic anemia. Karyotyping was normal. She underwent matched sibling transplantation. Her post-transplant course was uneventful with rapid engraftment. Cytogenetics showed 46, XX, inv (9), which was originated from her sister. She is now well at 70 months posttransplant. Case 3. A 3-year-old boy with ALL had a karyotype of 46, XY, inv (9) (p11q12). His clinical course was uneventful. CONCLUSION: The first case showed typical course of delayed recovery after chemotherapy and delayed engraftment after autologous transplantation. inv (9) should be considered in cases of otherwise unexplainable delay in recovery after chemotherapy or delayed engraftment after SCT. Further studies involving larger number of cases should be warranted to delineate the exact role of inv (9) in pediatric leukemia and SCTs.