In IgA MM (Table 5C) the subdivision according to beta-2 microglobulin levels has recorded, for values exceeding the median, a reduction of hemoglobin with an increase in RDW, while in IgG MM (Table 5D) the same analysis has highlighted a decrease in hematocrit and hemoglobin associated with an increase in RDW. Here, B2M is linked to Miyoshi myopathy.