{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T05:47:58Z","timestamp":1782712078469,"version":"3.54.5"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T00:00:00Z","timestamp":1782691200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004775","name":"Natural Science Foundation of Gansu Province","doi-asserted-by":"publisher","award":["22JR5RA669, 21GSSYB-29"],"award-info":[{"award-number":["22JR5RA669, 21GSSYB-29"]}],"id":[{"id":"10.13039\/501100004775","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>Anti-IgLON5 disease is a rare autoimmune neurological disorder characterized by anti- neuronal surface autoantibodies targeting the Immunoglobulin-Like Cell Adhesion Molecule 5 (IgLON5) protein. We report a 53-year-old male patient diagnosed with anti-IgLON5 disease who presented with the uncommon manifestation of generalized multi-site myokymia. Laboratory tests showed positive anti-IgLON5 IgG antibodies in both serum (titer 1:100) and cerebrospinal fluid (CSF) (titer 1:1), with no specific abnormalities detected on brain magnetic resonance imaging (MRI) and whole-exome sequencing. Considering patients\u2019 refusal to use high-dose glucocorticoids due to concerns about drug side effects, as well as the uncertainty surrounding the efficacy of intravenous immunoglobulin in treating IgLON5 disease, we selected a combined immunosuppressive therapy regimen consisting of intravenous neonatal fragment crystallizable receptor (FcRn) antagonist (efgartigimod) and sequential oral prednisone. The patient\u2019s myokymia were rapidly alleviated after combined treatment. During an 18-month follow-up, symptoms completely abated within the first 6 months, and antibody titers declined gradually to negative. Mild symptom recurred at 7 months post-initial treatment. Serum anti-IgLON5 IgG antibodies became positive (titer 1:10) at 14 months, however, these antibodies had been negative at 3 months after the start of treatment. Symptomatology was well-controlled after adjusting the oral prednisone dose. This case expands the clinical spectrum of anti-IgLON5 disease, highlights the necessity of screening for neuronal autoantibodies in patients with myokymia, and suggests that the combination of FcRn antagonists and glucocorticoids may emerge as a new immunotherapeutic option for this condition.<\/jats:p>","DOI":"10.3389\/fimmu.2026.1841316","type":"journal-article","created":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T05:40:09Z","timestamp":1782711609000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Anti-IgLON5 disease presenting with myokymia and favourable response to FcRN-antagonist combined with oral glucocorticoids: case report"],"prefix":"10.3389","volume":"17","author":[{"given":"Tianling","family":"Shang","sequence":"first","affiliation":[{"name":"Department of Neurology, Gansu Provincial Hospital","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Ma","sequence":"additional","affiliation":[{"name":"Department of Critical Care Medicine, Lanzhou University First Hospital","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shumei","family":"Wen","sequence":"additional","affiliation":[{"name":"Department of Neurology, Gansu Provincial Hospital","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zuohong","family":"Tang","sequence":"additional","affiliation":[{"name":"Department of Neurology, Gansu Provincial Hospital","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoliang","family":"Mao","sequence":"additional","affiliation":[{"name":"Department of Neurology, Gansu Provincial Hospital","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Keping","family":"Jiao","sequence":"additional","affiliation":[{"name":"Department of Neurology, Gansu Provincial Hospital","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,6,29]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.4103\/1673-5374.355742","article-title":"Anti-IgLON5 disease: a novel topic beyond neuroimmunology","volume":"18","author":"Zhang","year":"2023","journal-title":"Neural Regen Res"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0000000000012639","article-title":"Frequency and Characterization of Movement Disorders in Anti-IgLON5 Disease","volume":"97","author":"Gaig","year":"2021","journal-title":"Neurology"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/awac090","article-title":"Clinical, serological and genetic predictors of response to immunotherapy in anti-IgLON5 disease","volume":"146","author":"Gruter","year":"2023","journal-title":"Brain"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0000000000208101","article-title":"Development of a Composite Score for the Clinical Assessment of Anti-IgLON5 Disease","volume":"102","author":"Gaig","year":"2024","journal-title":"Neurology"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0000000000003887","article-title":"Clinical manifestations of the anti-IgLON5 disease","volume":"88","author":"Gaig","year":"2017","journal-title":"Neurology"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/116.2.453","article-title":"Immunological associations of acquired neuromyotonia (Isaacs' syndrome). 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