# Anti-LGI1 encephalitis and co-existence of MOG-IgG: a case report and literature review

## TL;DR

This paper reports a rare case of anti-LGI1 encephalitis co-occurring with MOG-IgG and reviews existing literature on the topic.

## Contribution

The study highlights the rare coexistence of anti-LGI1 encephalitis and MOG-IgG, emphasizing diagnostic challenges for clinicians.

## Key findings

- Nine papers involving 11 patients showed coexistence of anti-LGI1 and MOG-IgG.
- Most cases presented with encephalopathic symptoms, while some showed visual changes.
- Low MOG-IgG titers or CSF-only presence were associated with visual symptoms.

## Abstract

Anti-leucine-rich glioma-inactivated-1 (LGI1) encephalitis is an autoimmune disorder characterized by antibodies that target LGI1 (LGI1-IgG). It typically presents with cognitive impairment, psychiatric disturbances, and faciobrachial dystonic seizures (FBDS). Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is currently recognized as a demyelinating disease of the central nervous system (CNS) mediated by antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG). The co-occurrence of anti-LGI1 encephalitis and MOG-IgG is a rare phenomenon.

We report a case of anti-LGI1 antibody encephalitis combined with MOG-IgG. A comprehensive literature search was conducted using the PubMed and Embase databases. We utilized the following search terms: (“Limbic Encephalitis”[MeSH Terms] OR (“autoimmune encephalitis”[Title/Abstract] OR “AE”[Title/Abstract])) AND (“Myelin-Oligodendrocyte Glycoprotein”[MeSH Terms] OR “demyelinating autoimmune diseases, cns”[MeSH Terms] OR (“MOG-IgG”[Title/Abstract] OR “MOGAD”[Title/Abstract])). The search was constrained to the period from January 1, 2010, to December 31, 2024.

A total of nine papers involving 11 patients were included in the study. Three patients exhibited MOG-IgG in combination with LGI1-IgG. The majority of cases presented with encephalopathic symptoms. Visual changes were observed in a few cases with low titers of serum MOG-IgG or solely in the presence of MOG-IgG in the cerebrospinal fluid (CSF).

The occurrence of anti-LGI1 encephalitis alongside MOG-IgG is a relatively rare phenomenon. The clinical manifestation of encephalopathy in patients with coexisting antibodies presents a significant challenge for clinicians regarding timely diagnosis, highlighting the need for increased vigilance in daily practice.