Invited review: motor neuropathies, motor neuron disorders, and antiglycolipid antibodies.

High titers of IgM anti-GM1 antibodies are commonly found in the serum of patients with some lower motor neuron disorders and peripheral neuropathies. Enzyme-linked immunosorbent assays (ELISA) are useful for the detection and quantitation of anti-GM1 antibodies. Testing for serum anti-GM1 activity is indicated in the diagnostic evaluation of lower motor neuron syndromes. The presence of high titers of anti-GM1 antibodies mandates careful electrophysiologic testing for the motor conduction block that is found in multifocal motor neuropathy, a treatable disorder. Quantitation of anti-GM1 antibodies may also be a useful guide in the treatment of multifocal motor neuropathy. Further study of antiglycolipid antibodies in motor neuron disorders and peripheral neuropathies may provide clues to the events that stimulate these antibodies and to the pathogenesis of such syndromes.