High concentrations of GAD65 antibodies associate with a limited set of clinically distinctive phenotypes, namely: SPSD, cerebellar ataxia, epilepsy and limbic encephalitis (Fig. 3B), suggesting some syndrome specificity.107, 110, 111 In addition, several patients with GAD65 antibodies do respond to immunotherapy. Here, GAD2 is linked to aceruloplasminemia.