[Clinical amyotrophic lateral sclerosis syndromes in gammapathies: clinical, electrophysiologic and histoimmunologic aspects].

Eleven patients with motor neuron disease associated with a monoclonal gammopathy were studied. One patient had a previously known multiple myeloma. In the other patients neurological symptoms preceded diagnosis of the gammopathy by one month to 8 years. They were 5 multiple myeloma, 1 macroglobulinemia, 1 chronic lymphatic leukemia, 1 lymphoma and 3 benign monoclonal gammopathies. EMG and motor conduction velocities results were consistent with anterior horn cell disease but sensory conduction studies were abnormal in seven cases out of eight. Superficial peroneal nerve biopsy performed in all patients confirmed peripheral nerve involvement. The relations between gammopathy, clinical symptoms and electrophysiological data are discussed. The interest of sensory conduction studies in every patient with motor neuron disease is emphasized.