Cerebellar Ataxia With Anti-Glutamic Acid Decarboxylase Antibodies

brainstem involvement. Ten patients had oligoclonal IgG bands in the cerebrospinal fluid, and intrathecal GAD-Ab synthesis was observed in 5 of the 6 patients studied. The level of GAD-Ab of these patients was similar to those with stiff-man syndrome and significantly higher than those with IDDM or with polyendocrine autoimmunity (P,.001). However, the GAD-Ab levels of 6 of the 9 patients with polyendocrine autoimmunity overlapped with those of patients with cerebellar ataxia. Conclusions: These results suggest a link between high level of GAD-Ab and some cases of cerebellar ataxia, particularly women with IDDM. If high serum levels of GAD-Ab are detected, the cerebrospinal fluid should be evaluated for the presence of oligoclonal IgG bands and intrathecal synthesis of GAD-Ab to further prove an autoimmune origin of the syndrome.