The mechanisms of AVWS may differ between IgG and IgM gammopathy. Loss of HMW multimers has been specifically noted in the presence of an IgM gammopathy and may affect the treatment options [11]. Classically Waldenstrom’s macroglobulinemia is associated with elevated IgM levels and can be complicated by hyperviscosity. The gene discussed is CD40LG; the disease is Waldenstrom macroglobulinemia.