Mu Chain Disease, also known as mu-chain disease, is related to agammaglobulinemia and heavy chain disease. An important gene associated with Mu Chain Disease is VPREB1 (V-Set Pre-B Cell Surrogate Light Chain 1), and among its related pathways/superpathways are Response to elevated platelet cytosolic Ca2+ and Cell surface interactions at the vascular wall. Related phenotypes are Increased shRNA abundance (Z-score > 2) and immune system