In the IgM monoclonal gammopathy group, among the histopathological findings were: various degrees of loss of myelinated fibers, association of demyelination and axonal lesions revealed through electronic microscopy in all eight cases, macrophage-associated demyelination in six cases, segmental demyelination and “onion bulb” formation in all eight cases. The gene discussed is CD40LG; the disease is monoclonal gammopathy.