[A case of motor neuron disease with IgM gammopathy which showed anti-cerebrum antibody].

A patient, 50-year-old female, developed progressive weakness of lower extremities, and gait disturbance for 2 years. Neurological examination revealed hyperreflexia with pathological reflex, fasciculation in the limbs and tongue, muscle weakness and atrophy in distal limbs, but no sensory disturbance. Needle EMG showed neurogenic findings compatible with motor neuron disease (MND). Laboratory data showed polyclonal IgM hyperimmunoglobulinemia, positive several autoimmune antibodies including antisingle strand DNA antibody (Ab), ENAab, SS-A ab and RA. There were no antibodies for gangliosides and Myelin-associated glycoprotein (MAG), but positive antibody for 54KD protein of cerebral gray and white matter. The clinical manifestations including gait disturbance and muscle weakness, and serum IgM level were moderately improved by plasmapheresis which is considered important for consideration of causes of MND.