To provide a comprehensive understanding of the expression and localization of OGT and O-GlcNAcylation in MM, we compared the expression patterns of OGT and O-GlcNAcylation in purified CD138+ plasma cells isolated from healthy control (HC) peripheral blood mononuclear cells (PBMCs) and the MM patient-derived cell line (MM.1S). This evidence concerns the gene SDC1 and Miyoshi myopathy.