This is the first study to reveal the asymmetry of LGI1 protein expression in the human brain; the patients with LGI1-antibody encephalitis had asymmetric FDG-PET images displaying increased FDG uptake on the contralateral hemisphere to the handedness (the dominant hemisphere), and the human brain samples expressed more LGI1 protein on the left globus pallidus (possibly dominant side). Here, LGI1 is linked to encephalitis.