LGI1 and Isaacs syndrome: From 31 patients (28/31 with limbic encephalitis, including 12/31 with FBDS, 1/31 FBDS only, 1/31 Morvan’s syndrome, 1/31 neuromyotonia/pain), median serum autoantibody levels to membrane-tethered full-length LGI1 were 80-fold higher than CSF (Fig. 1B), consistent with peripheral antibody generation.