Anti-Glutamic Acid Decarboxylase (GAD) encephalitis: Anti-GAD antibodies are not typically associated with malignancy but associated with other non-neoplastic autoimmune conditions such as type 1 diabetes mellitus. Classic temporal lobe lesions on magnetic resonance (MR) imaging with the expected clinical findings of limbic encephalitis plus additional features of stiff person syndrome. The gene discussed is GAD1; the disease is diabetes mellitus.