Antibodies to the ganglioside GD1b in a patient with motor neuron disease and thyroid adenoma.

Patients with motor neuron disease with thyroid disorders have been described, although the relationship between the two conditions is unclear. We treated a patient with amyotrophic lateral sclerosis who also had a follicular adenoma of the thyroid gland. Because thyroid gland plasma membranes contain high concentrations of complex gangliosides, such as GD1b, and some patients with motor neuron disease have IgM antibodies to GD1b, we decided to assay serum from this patient for the presence of antiganglioside antibodies. IgM antibodies to GD1b were detectable at serum dilutions of 1:500 and 1:1000 by enzyme-linked immunosorbent assay. While these titers are less than those usually described in patients with plasma cell dyscrasia, they are well in excess of normal values. Antibody to GM1 was also detectable at a lower (1:100) dilution. We do not know the importance of the anti-GD1b antibodies in this patient, but it is possible that antibodies to GD1b are involved in this and other cases of motor neuron disease associated with thyroid disease.