Of these 13 patients, 1 switched from IgM-k to λ-FLC only; 7, respectively, switched from k FLC only (2 patients)/IgG-k/IgD-k/IgA-λ/IgA-k (2 patients) to non-secretory MM; 1 switched from IgD-λ to IgG-k with P53 deletion; 2 switched to k-FLC only from original IgA-k and IgG-k paraprotein; 1 switched from non-secretory MM to λ-FLC only. The gene discussed is CD40LG; the disease is Miyoshi myopathy.