A unique combination of autoimmune limbic encephalitis, type 1 diabetes, and Stiff person syndrome associated with GAD-65 antibody

Antibodies to GAD-65 have been implicated in the pathogenesis of type 1 diabetes, limbic encephalitis and Stiff person syndrome, however these diseases rarely occur concurrently. We intend to present a rare case of 35 year old female who was recently diagnosed as having type 1 diabetes presented with 1½ month history of recurrent seizures, subacute onset gait ataxia, dysathria, psychiatric disturbance and cognitive decline. No tumor was found on imaging and the classic paraneoplastic panel was negative. Cerebrospinal fluid and blood was positive for GAD-65 antibodies. Patient showed significant improvement with immunomodulatory therapy. Association of GAD-65 antibodies has been found with various disorders including type 1 diabetes, limbic encephalitis, Stiff person syndrome, cerebellar ataxia and palatal myoclonus. This case presents with unique combination of type 1 diabetes, Stiff person syndrome and limbic encephalitis associated with GAD-65 antibodies that is responsive to immunotherapy. It also highlights the emerging concept of autoimmunity in the causation of various disorders and there associations.