CD79A and Miyoshi myopathy: The most frequently found isotype of monoclonal immunoglobulins (Ig) in MM patients is IgG, accounted for 52% of all cases, followed by IgA, described in 21% of subjects, and light-chain-only secretion in 16%, while IgD and IgM phenotypes are rare (2% and 0.5% of cases, respectively) [8].