GAD1 and systemic lupus erythematosus: With the discovery of NMDA-receptor encephalitis, and its ability to mimic mental disorders, the interest spiked further, and with GAD-antibodies being able to induce limbic encephalitis (59, 60) and antibodies reacting with the NR2 subunit of NMDA being present in some cases of lupus (61), a possible link emerged.