Moreover, we observed a complex pattern of aberrant PC marker upregulation in some subsets of B cells, such as CD200 (pre-BI, transitional, and naive B cells), CD28 (naive B cells and switched memory B cells), sXBP-1 (in the B cell precursors pre-pro-B and pro-B cells, transitional B cells, and unswitched memory B cells), and CD319 (switched memory B cells) in our MM cohort. The gene discussed is CD200; the disease is Miyoshi myopathy.