Abstract
BackgroundSMARCD2 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2) has recently been shown to have a critical role in granulopoiesis in humans, mice, and zebrafish. Our patient presented with delayed cord separation, failure to thrive, and sepsis. Retrospective whole-exome sequencing confirmed a homozygous splice-site mutation in SMARCD2.ObjectiveWe sought to provide the second description of human SMARCD2 deficiency and the first functional analysis of human primary SMARCD2-deficient cells.MethodsHeparinized venous blood and bone marrow were collected from the patient after obtaining informed consent. Patient leukocytes and CD34+ cells were then isolated, phenotyped, and assessed functionally.ResultsCirculating neutrophils appeared phenotypically immature, lacking multilobed nuclei, and neutrophil granules lacked lactoferrin but showed normal levels of myeloperoxidase. Neutrophil oxidative burst was preserved in response to phorbol 12-myristate 13-acetate. Patient bone marrow–derived neutrophils and white blood cells showed a severely impaired chemotactic response. Furthermore, white blood cells showed defective in vitro killing of Staphylococcus aureus, consistent with a specific granule deficiency. Finally, patient bone marrow–derived CD34+ cells showed markedly impaired in vitro expansion and differentiation toward the neutrophil lineage. Before her molecular diagnosis, our patient underwent hematopoietic stem cell transplantation and is well 8 years later.ConclusionsThis report highlights an important role for SMARCD2 in human myelopoiesis and the curative effect of hematopoietic stem cell transplantation for the hematopoietic features of SMARCD2 deficiency.
Highlights
The chromatin-remodeling factor SMARCD2 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2) plays an important role in myeloid differentiation in humans
Neutrophil oxidative burst was preserved in response to phorbol 12-myristate 13-acetate
SMARCD2: SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2 second report of human SMARCD2 deficiency leading to neutrophil-specific granule deficiency
Summary
SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2) plays an important role in myeloid differentiation in humans. We present the first analysis of human SMARCD2-deficient primary cells and the. SMARCD2: SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2 second report of human SMARCD2 deficiency leading to neutrophil-specific granule deficiency. SMARCD2 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2) has recently been shown to have a critical role in granulopoiesis in humans, mice, and zebrafish. Objective: We sought to provide the second description of human SMARCD2 deficiency and the first functional analysis of human primary SMARCD2-deficient cells. Patient leukocytes and CD341 cells were isolated, phenotyped, and assessed functionally
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