To investigate potential pathogenic effects of SynI autoantibodies, we treated primary neurons with the CSF of a limbic encephalitis and clinical isolated syndrome patients (herein referred to as LE-CSF and CIS-CSF, respectively) that were characterized by high titers of IgG and IgA autoantibodies against SynI13,14. The gene discussed is SYN1; the disease is in situ carcinoma.