Among 377 patients with IgM-related disorders, the most common diagnoses were MGUS (42%), WM (28%), B-cell NHL such as CLL, extranodal marginal zone lymphoma, and splenic marginal zone lymphoma (18%), primary cold agglutinin disease (4%), AL amyloidosis (4%), cryoglobulinemia (2%), and IgM MGUS-associated neuropathy (1%)31. The gene discussed is CD40LG; the disease is AL amyloidosis.