Anti‐ IgLON5 Disease: A Systematic Review and Meta‐Analysis

Background Anti‐IgLON5 disease is now considered a complex and heterogeneous neurological disorder with sleep, movement, and neuroimmunological as well as neurodegenerative aspects. The aim of this systematic review and meta‐analysis was to entail the whole clinical spectrum as well as laboratory characteristics, therapeutic interventions and reported outcomes of anti‐IgLON5 disease. Methods The electronic databases PubMed/MEDLINE, Web of Science and Semantic Scholar were searched for case reports and case series on anti‐IgLON5 disease published until July 31, 2024. For inclusion, studies had to report on patients with a positive IgLON5 antibody titer in serum or CSF and be published in English in a peer‐reviewed journal. For meta‐analyses, only case series with N ≥ 10 patients were considered. The risk of bias was assessed with the JBI critical appraisal tool. Results A total of 285 patients ( N case series/case reports = 85) with anti‐IgLON5 disease were included in this systematic review. Sleep abnormalities ( N = 218; 76.5%), bulbar dysfunction ( N = 175; 61.4%) and movement disorders ( N = 160; 56.1%) were most frequently reported. The prevalence of IgLON5 antibodies in the serum was 99.6% ( N reported = 276). Conclusion Based on our results, anti‐IgLON5 disease should be considered in patients presenting with sleep disorders and additional neurological symptoms that might resemble other diseases but do not fulfill the respective diagnostic criteria. Testing for antibodies in serum has a high sensitivity in this disorder. A limitation of this study is that it was not preregistered.