Previous groups have successively described various CSC phenotypes in MM, including CD138-/CD34- with memory B-cells (CD19+/CD27+) [4, 5], CD138-/CD19+ cells with cytoplasmic light chain-restricted (LCR) cells [6], CD19-/CD45low-/CD38high/CD138+ [7], and CD138+ cell [8]. The gene discussed is CD19; the disease is Miyoshi myopathy.