CEREBELLAR-ATAXIA AND POLYNEUROPATHY IN A PATIENT WITH IGM M-PROTEIN SPECIFIC TO THE GAL(BETA-1-3)GALNAC EPITOPE

A 79-year-old man with sensory dominant polyneuropathy, cerebellar ata xia, and palatal myoclonus had serum IgM M-protein that specifically b ound to GM1, GD1b, and asialo-GM1. IgM with the same specificity was d etected in his cerebrospinal fluid. Results of immunohistochemical stu dies showed specific binding of this monoclonal IgM to the cerebellar granular layer, dentate nucleus, inferior olive, and gray matter of th e cerebrum and spinal cord. Monoclonal antibody GGR12, monospecific to GD1b, had an immunostaining distribution similar to that of the patie nt's IgM M-protein. The binding of M-protein may be associated with th e development of cerebellar ataxia and palatal myoclonus in this patie nt.