GAD2 and paraneoplastic neurologic syndrome: Furthermore, the haplotype DR3 ~ DQ2 has been related to a few autoimmune encephalitis and PNS, principally to neurological syndromes with antibodies against glutamic acid decarboxylase 65 (GAD65) and limbic encephalitis with adenylate kinase 5 (AK5) antibodies [17, 18].