Comparison of the clinical syndromes of anti-GABAa versus anti-GABAb associated autoimmune encephalitis: A systematic review

The main objective of this article is to improve our understanding of the differences and similarities of these two anti-gamma-aminobutyric acid receptor encephalitis, anti-GABAaR and anti-GABAbR. The data were systematically collected and we found 26 studies: seven studies and 37 patients corresponded to anti-GABAaR encephalitis, and 21 manuscripts and 116 patients were diagnosed with anti-GABAbR encephalitis. Both anti-GABAR encephalitis were marked by prominent seizures. Anti-GABAaR patients were younger and showed multifocal encephalitis. On the other hand, anti-GABAbR patients were older and showed temporal limbic encephalitis. Tumor occurred in a fifth of anti-GABAaR encephalitis and in half of anti-GABAbR encephalitis. The main tumor associated with anti-GABAbR encephalitis is SCLC, whereas the most common tumor associated with anti-GABAaR encephalitis was thymoma. Our data confirms the differences in clinical features between both encephalitis.