GAD2 and cerebellar ataxia: Baekkeskov et al. in 1990 firstly described that the level of the GAD65-Abs in stiff person syndrome was 10–200 times higher than in DM1 patients on the basis of an immunoprecipitation method, and later Honnorat et al. in 2001 found similar results in patients with cerebellar ataxia compared to patients with DM1 using RIA and IHC (with the staining pattern of GAD65-Abs on rat cerebellum) (1, 20).