Overproduction of a single abnormal clone of a plasma cell or B lymphocyte results in the presence of a monoclonal gammopathy.1 Disorders associated with the presence of a monoclonal protein (M protein) include B-cell lymphomas and leukaemias; amyloidosis and Waldenstrom’s macroglobulinaemia; and plasma cell dyscrasias, which include multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS) and plasmacytoma.2 MGUS is a premalignant plasma cell disorder with an associated risk of progression to multiple myeloma (MM). This evidence concerns the gene MYOM2 and Miyoshi myopathy.