Anti-GAD Antibodies as an Etiology of Cerebral Cortical Encephalitis:2 Case Reports.

Introduction: Cerebral cortical encephalitis (CCE) has been recently described as an entity associated with anti-MOG antibod-ies and, in some cases, of anti- GABA A R encephalitis. No clear association with other antibodies has been reported to date. Wedescribe two cases of patients presenting clinical and radiological features of diffuse cortical encephalitis associated with anti-GAD antibodies.Method: In two patients with CCE, screening for the presence of anti- GAD and other antibodies was performed, along with acomplete workup for alternative diagnoses.Results: Two patients showing clinical and radiological features of CCE were tested positive for anti- GAD antibodies. MRI scanrevealed multiple bilateral areas of cortico-subcortical FLAIR hyperintensities. They were both tested negative for anti-MOG,anti-NMDAr, and anti- GABA A R antibodies. An ovarian teratoma was discovered in patient 1. Clinical and radiological evolutionwas favorable in both patients after cumulated therapies in the acute phase.Discussion: CCE could be a new manifestation of anti- GAD antibodies, with distinct features compared to anti-MOG antibodiesrelated to CCE. We recommend screening for anti- GAD antibodies in the context of CCE, especially in case of atypical featuresfor MOG antibodies-associated disease (MOGAD).