Also, for IgM MM, likely other myelomas, CRAB (hypercalcemia, renal failure, anemia, and bone lesions) criteria, and myeloma-defining events (bone marrow plasma cells > 60%, kappa/lambda ratio ≥ 100, > 1 magnetic resonance imaging focal lesion) lead treatment decisions [1, 3]. The gene discussed is CD40LG; the disease is plasma cell myeloma.