Improvement of GAD65-associated autoimmune epilepsy with testosterone replacement therapy

Treatment response in autoimmune epilepsy is variable. Achieving seizure reduction is often dependent on the specific neuronal antibody. Glutamic acid decarboxylase 65 (GAD65)-associated epilepsy is among the most challenging of the autoimmune epilepsies to treat, often requiring multiple antiepileptic drugs (AEDs) and aggressive immunotherapy to attain a reduction in seizure frequency. There have been reports of improvement in seizure frequency in nonautoimmune epilepsy following administration of testosterone. However, the association between sex steroids and autoimmunity is not clear, with no established association of sex hormone responsiveness in cases of autoimmune epilepsy. We present a case of immunotherapyand AED-resistant GAD65-associated autoimmune epilepsy demonstrating sustained improvement with exogenous testosterone replacement.