SEC23B encodes a core component of the COPII coat protein complex that mediates vesicle transport from the endoplasmic reticulum to the Golgi apparatus 1. This protein is essential for normal erythroid differentiation, as SEC23B mutations cause congenital dyserythropoietic anemia type II (CDAII), the most common form of CDA 12. CDAII is characterized by ineffective erythropoiesis, bi- and multinucleated erythroblasts with cytokinesis defects, and progressive complications including splenomegaly, iron overload, and liver cirrhosis 13. Although SEC23A and SEC23B are paralogous genes with interchangeable biochemical functions, they exhibit tissue-specific expression patterns that explain their distinct clinical phenotypes - SEC23B is predominantly expressed in human bone marrow while SEC23A dominates in pancreas 4. Complete SEC23B deficiency in mice causes perinatal lethality with massive degeneration of secretory tissues, while partial deficiency leads to growth restriction, chr20 pancreatitis, and growth hormone insensitivity 5. SEC23B protein levels are significantly reduced in CDAII patients, correlating with decreased mRNA expression 6. Recent studies have identified SEC23B as a target of OTUD1-mediated deubiquitination, which regulates COPII-dependent secretory pathways in neutrophils 7.