A rare neuroendocrine presentation in pediatric anti-glutamic acid decarboxylase autoimmunity: Case report and literature review

Abstract

Anti-glutamic acid decarboxylase (anti-GAD) antibodies are commonly associated with type 1 diabetes mellitus (T1DM) but can also indicate severe neurological involvement, including autoimmune encephalitis. We present the case of a previously healthy four-year-old girl who developed persistent focal epileptic seizures affecting the right hemiface, which progressed to epilepsia partialis continua and were accompanied by hyperglycemia and signs of premature thelarche. Additional findings included advanced bone age and a single episode of unexplained vaginal bleeding. Brain MRI and abdominal ultrasound were unremarkable, but EEG revealed left temporal spikes. Laboratory testing confirmed elevated anti-GAD antibodies (>2000 IU/mL), supporting a diagnosis of autoimmune encephalitis. The patient was treated with intravenous immunoglobulin (IVIG), resulting in partial seizure control and improved glycemic regulation. This case underscores the need to consider autoimmune mechanisms in pediatric patients with pharmacoresistant seizures and concurrent endocrine abnormalities. Early identification of anti-GAD antibodies facilitated timely immunotherapy, emphasizing the value of integrated diagnostic and therapeutic strategies in managing rare autoimmune disorders.