NEUROPATHIES ASSOCIATED WITH MONOCLONAL GAMMOPATHIES

Approximately 10% of patients with idiopathic peripheral neuropathy ha ve an associated serum monoclonal gammopathy or M-protein. This repres ents six times the incidence of M-proteins found in the general popula tion. In 5% of idiopathic peripheral neuropathy patients the M-protein is associated with an identifiable plasma cell dyscrasia. Sclerotic m yeloma is particularly important to recognize because treatment may re sult in amelioration of the neuropathy and remission of the tumor. Pat ients with primary systemic amyloidosis often have preferential small fiber involvement with a dissociated sensory loss and autonomic dysfun ction. The nerve root infiltration of lymphoproliferative disorders ma y simulate a polyradiculoneuropathy. In cases without an identifiable cause for the M-protein, referred to as monoclonal gammopathy of undet ermined significance (MGUS), the pathophysiologic basis for the neurop athy is poorly defined in most cases. A role for M-proteins with antib ody activity to myelin-associated glycoprotein is provocative. This re view summarizes current knowledge of this important group of disorders .