LGI1 expression and human brain asymmetry: insights from patients with LGI1-antibody encephalitis

J Neuroinflammation. 2018 Sep 25;15(1):279. doi: 10.1186/s12974-018-1314-2.


Background: While brain asymmetry has been a fascinating issue in neuroscience, the critical mechanism remains to be elucidated. Based on some index cases with asymmetric 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) uptake in leucine-rich glioma-inactivated 1 (LGI1)-antibody encephalitis, we hypothesized LGI1 expression could be asymmetrically distributed in the human brain.

Methods: We enrolled 13 patients who were diagnosed with LGI1-antibody encephalitis between June 2012 and January 2018 at Seoul National University Hospital. Their pretreatment 18F-FDG-PET images were analyzed to find asymmetry between the left and right hemispheres. Guided by these observations, expression of LGI1 in the human hippocampus and the globus pallidus of both cerebral hemispheres was studied in nine post-mortem human brains.

Results: Eleven of the 13 LGI1-antibody encephalitis patients (84.6%) showed asymmetrical FDG high uptake in the hippocampus: nine (81.8%) on the left hippocampus and two (18.2%) on the right. In the basal ganglia, seven patients (53.8%) showed asymmetry: four (57.1%) on the left and three (42.9%) on the right. The asymmetry was not evident in the laterality of faciobrachial dystonic seizures, brain MRI, and EEG. When the expression of LGI1 protein was analyzed in nine post-mortem human brains by western blotting, LGI1 expression was higher on eight left globus pallidus samples (88.89%, P = 0.019) and on four left hippocampal samples (44.44%, P = 0.652), compared to their right hemisphere samples.

Conclusions: Imaging parameters from patients with LGI1-antibody encephalitis and studies of LGI1 protein expression suggest that LGI1 is asymmetrically distributed in the human brain. These observations have implications for our understanding of human brain development.

Keywords: Autoantibody; Brain lateralization; Human brain asymmetry; LGI1; LGI1 encephalitis.

MeSH terms

  • Aged
  • Autoantibodies / blood*
  • Brain / diagnostic imaging
  • Brain / metabolism*
  • Electroencephalography
  • Encephalitis / diagnostic imaging
  • Encephalitis / immunology*
  • Encephalitis / pathology*
  • Female
  • Fluorodeoxyglucose F18 / pharmacokinetics
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Nerve Tissue Proteins / metabolism
  • Positron-Emission Tomography
  • Proteins / genetics
  • Proteins / metabolism*
  • Retrospective Studies
  • Statistics, Nonparametric


  • Autoantibodies
  • Intracellular Signaling Peptides and Proteins
  • LGI1 protein, human
  • Nerve Tissue Proteins
  • Proteins
  • Fluorodeoxyglucose F18