Successful allogeneic stem cell transplantation with fludarabine-based reduced intensity conditioning in bone marrow failure syndrome 4.

BACKGROUND: Myb-like, SWIRM, and MPN domains 1 (MYSM1) is a histone H2A deubiquitinase, has been discovered as one of the transcriptional regulators, and regulates the expression of specific transcription factors, which are essential for immunohematology development. Mutation in MYSM1 in humans leads to a rare autosomal recessive disease that has recently been known as inherited bone marrow failure syndrome 4 (BMFS4) associated with congenital bone marrow failure, immunodeficiency, and developmental aberrations. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative option for immunohematology defects. METHODS: In this paper, we report a pediatric patient with BMFS4 who suffered from pancytopenia and immunodeficiency affecting B cells and was successfully treated with HSCT from an HLA-identical father at 6 years old of age. Fludarabine-based reduced intensity conditioning was used and resulted in full donor chimerism. RESULTS: Acute graft versus host disease (GVHD) grade II involving skin and gastrointestinal tract was observed, which was controlled with prednisolone. CONCLUSION: She achieved B-cell recovery, and no blood or platelet transfusion was reported 1 year after HSCT.