INTRODUCTION
Diamond-Blackfan anemia (DBA) is a rare inherited bone marrow failure
syndrome (IBMFS) characterized by hypoproliferative and proapoptotic
erythropoiesis along with malformations and cancer
predisposition.1 The pure red cell aplasia (PRCA)
arises from haploinsufficiency due to a loss of function mutation in
ribosomal protein (RP)-encoding genes. Corticosteroids are the
first-line treatment for PRCA in infancy, but >20% of
patients result in transfusion-dependency. Patients are predisposed to
myeloid malignancy and solid tumors. In pediatric patients, the 5-year
chronic graft-versus-host-disease (GVHD)-free survival rate following
allogeneic hematopoietic cell transplantation (HCT) has improved to
87.0%, including mostly histocompatible sibling or unrelated
donors.2 HCT can
achieve a hematological cure transfusion-dependent young patients if a
suitable donor is available. Nevertheless, conditioning of alternate
donor HCT is carefully personalized according to organ dysfunctions
associated with the ribosomopathy by itself and iron-overload.
Regarding cancer predisposition
and the high risk of complications, reduced intensity conditioning (RIC)
is preferable; however, there is limited information on unrelated donor
HCT.3-7 To optimize the HCT regimen for DBA, we
assessed the outcomes of recent cases with alternate donor bone marrow
transplantation (BMT) following targeted busulfan (BU)-based
intermediate intensity conditioning.