Anti-GABAB receptor encephalitis combined with autoimmune polyendocrine gland syndrome

Anti-GABAB receptor encephalitis coexistence with autoimmune polyendocrine syndrome (APS) has not been reported. We present the first case of anti-GABAB receptor encephalitis coexisting with APS type III. A 64-year-old male presented with recurrent convulsions with loss of consciousness. Diagnostic evaluation revealed positive anti-GABAB receptor antibodies, elevated HbA1cand fasting blood glucose, and glutamic aciddecarboxylase antibodies (GAD-Ab), hypothyroidism with positive thyroglobulin and peroxidase antibody. The patient demonstrated complete diagnostic criteria for both anti-GABAB receptor encephalitis and APS type III. A Combination therapy with pulse corticosteroids, intravenous immunoglobulin, levothyroxine, and insulin achieved significant clinical improvement. The findings expand the spectrum of autoimmune overlap syndromes and highlight diagnostic challenges in patients presenting with concurrent neurological and endocrine dysfunction.