Inadvertent Transmission of a Donor’s Constitutional Chromosome Abnormality after Hematopoietic Stem Cell Transplantation

A pre-transplant screening work-up of donors for allogeneic hematopoietic stem cell transplantation (HSCT) is essential. Inadvertent transmission of malignancy from donors with subclinical diseases to recipients has been reported recently in several cases. A 49-year-old male was diagnosed with acute myeloid leukemia. He underwent a course of induction chemotherapy and achieved cytogenetic complete remission (CR). He was treated with an additional cycle of consolidation chemotherapy followed by full matched sibling allogeneic HSCT due to an additional deletion in 9q known as an adverse prognostic factor. Post transplantation bone marrow biopsy revealed molecular CR, but conventional cytogenetics identified the presence of 46,XY,t(1:2)(p32:q35). A cytogenetic analysis of the donor graft specimen revealed t(1:2). We confirmed the donor origin of t(1:2). We report the first case of a person with constitutional t(1;2) serving as a stem cell donor.