Autoantibodies to the smaller isoform (GAD65Ab) can be found in patients with type 1 diabetes, and a number of neurological disorders, including stiff-person syndrome (SPS), cerebellar ataxia (Björk et al., 1994; Honnorat et al., 2001; Rakocevic et al., 2006), and limbic encephalitis (Matà et al., 2010) while GAD67 is rarely autoantigenic. This evidence concerns the gene GAD1 and type 1 diabetes mellitus.