Successful cord blood transplantation for a unique case of bone marrow failure presenting t(2;19)(p23;q13.3) translocation suggesting disruption of DPY30.

H3K4 methylation, primarily mediated by MLL family proteins, plays a pivotal role in the epigenetic regulation of gene transcription. Among the MLL family, KMT2A is known for its critical role in hematopoiesis. MLL family proteins feature C-terminal SET catalytic domains, requiring the formation of MLL complexes with proteins like DPY30 to maximize their enzymatic activity. Deletion of DPY30 results in a significant reduction in H3K4me1, H3K4me2, and H3K4me3 levels in bone marrow (BM) cells, underscoring the essential role of DPY30 in facilitating optimal catalytic activity within MLL family complexes. Here, we present a unique case of myelodysplastic neoplasms (MDS) associated with a novel t(2;19)(p23;q13.3) translocation. A 22-year-old pregnant woman initially sought consultation due to thrombocytopenia, which temporarily improved following a miscarriage. However, she later presented with progressive pancytopenia. RNA sequencing analysis of BM mononuclear cells using STAR-Fusion revealed the translocation breakpoint on chromosomes, resulting in the disruption of the DPY30 and CEACAM6 genes. BM failure showed marked improvement following cord blood transplantation. This case represents a novel form of MDS associated with the disruption of the DPY30 gene. Our findings underscore the importance of considering early hematopoietic stem cell transplantation for MDS cases attributed to DPY30 dysfunction.