The most striking cases concerned: (i) IGHV3-30 in IgA MM, where 4/20 cases (20%) recombined with IGHD3-10, (ii) IGHV4-59 in IgG MM, where 5/16 cases (31%) recombined with IGHD2-21. The gene discussed is BTK; the disease is Miyoshi myopathy.