Familial occurrences of Waldenstrom macroglobulinemia, a rare subtype of non-Hodgkin lymphoma, are uncommon but well described (Renier et al. 1989; Blattner et al. 1980). It has been suggested that 4 % of relatives of affected persons have a monoclonal IgM component (Kalff and Hijmans 1969). In the family of Blattner et al. (1980), all four affected relatives had a common HLA haplotype (A2, B8, DRw3). However, in the other two reports, no consistent HLA associations were found. The monoclonal IgM light chain type may differ between relatives with familial Waldenstrom macroglobulinemia, as occurred in monozygotic twins with Waldenstrom macroglobulinemia (Fine et al. 1986). Autoimmune disorders and immunoglobulin abnormalities are frequent in relatives of patients with familial Waldenstrom macroglobulinemia, suggesting that in these families Waldenstrom macroglobulinemia may be one manifestation of a genetic predisposition to abnormal immunoglobulin synthesis control mechanisms (McMaster 2003). Linkage of WM to chromosome 4q has been described (McMaster et al. 2006). Only 4 of 200 healthy controls (2 %) were found to be carriers of paratarg-7 (pP-7), whereas pP-7 carrier state was associated with a significantly increased risk (odds ratio = 6.2; P = .001) for developing IgM-MGUS/Waldenstrom macroglobulinemia. The pP-7 carrier state is inherited as a dominant trait. After IgA/IgG-MGUS and multiple myeloma, IgM-MGUS/WM is the second neoplasia associated with pP-7 carrier state (Grass et al. 2011).