{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T19:42:29Z","timestamp":1780083749248,"version":"3.54.0"},"reference-count":39,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T00:00:00Z","timestamp":1768780800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Anti-GQ1b antibody syndrome (AGABS) unifies triad-defined Miller Fisher syndrome (MFS), Bickerstaff brainstem encephalitis (BBE), and the ophthalmoplegic variant of Guillain\u2013Barr\u00e9 syndrome (GBS-O) under a post-infectious immune mechanism centered on IgG to disialosyl gangliosides. The spectrum also encompasses triad-minus phenotypes\u2014acute ophthalmoparesis without ataxia, acute vestibular syndrome, optic involvement, and acute sensory-ataxic neuropathy. A molecular-mimicry model with complement-mediated nodal\/paranodal dysfunction explains severe early deficits despite bland limb nerve conduction studies (NCSs), the cranial\/proprioceptive predilection, and generally favorable treatment responsiveness to immunotherapy. In practice, a serology-first strategy, complemented by targeted electrophysiology\u2014blink and H-reflex testing, and, where feasible, paired SEP\u2013ABR showing a literature-supported dissociation (normal ABR with impaired median-nerve cortical SEPs), which, in our series, was documented in one illustrative BBE case\u2014and by structured neuro-otologic examination, mitigates the \u201cnormal-NCS trap\u201d and enables timely treatment. Intravenous immunoglobulin (IVIg) is first-line; plasma exchange (PLEX) is an alternative in severe or IVIg-ineligible cases; and intravenous methylprednisolone (IVMP) may be added selectively for central\/optic-weighted phenotypes without routine oral taper. We consolidate actionable diagnostic and therapeutic steps and examine them in an institutional series of 16 consecutive seropositive patients (2015\u20132025): all were anti-GQ1b-positive with frequent GT1a co-reactivity; most reported an antecedent infection\u2014typically upper respiratory, less often gastrointestinal\u2014within the two weeks before onset; limb NCSs were often nondiagnostic whereas reflex\/evoked-potential studies were informative; two required intubation in addition to IVIg; outcomes were generally favorable with early immunotherapy. The practical message: order anti-GQ1b at first contact, pair targeted electrophysiology with neuro-otology, and treat early to exploit reversible nodal\/paranodal dysfunction.<\/jats:p>","DOI":"10.3390\/jcm15020801","type":"journal-article","created":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T09:24:34Z","timestamp":1768901074000},"page":"801","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Anti-GQ1b Antibody Syndrome: A Clinician-Oriented Perspective on Diagnostics, Therapy, and Atypical Phenotypes\u2014With an Illustrative 16-Case Institutional Series"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1664-1932","authenticated-orcid":false,"given":"Taro","family":"Bannai","sequence":"first","affiliation":[{"name":"Department of Neurology, Tokyo Teishin Hospital, Tokyo 102-8798, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4970-0994","authenticated-orcid":false,"given":"Minako","family":"Yamada","sequence":"additional","affiliation":[{"name":"Department of Neurology, Tokyo Teishin Hospital, Tokyo 102-8798, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-6154-5562","authenticated-orcid":false,"given":"Tomonari","family":"Seki","sequence":"additional","affiliation":[{"name":"Department of Neurology, Tokyo Teishin Hospital, Tokyo 102-8798, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasushi","family":"Shiio","sequence":"additional","affiliation":[{"name":"Department of Neurology, Tokyo Teishin Hospital, Tokyo 102-8798, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3608-0973","authenticated-orcid":false,"given":"Tatsuya","family":"Yamasoba","sequence":"additional","affiliation":[{"name":"Department of Otolaryngology, Tokyo Teishin Hospital, Tokyo 102-8798, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2294","DOI":"10.1056\/NEJMra1114525","article-title":"Guillain\u2013Barr\u00e9 syndrome","volume":"366","author":"Yuki","year":"2012","journal-title":"N. Engl. J. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"717","DOI":"10.1016\/S0140-6736(16)00339-1","article-title":"Guillain\u2013Barr\u00e9 syndrome","volume":"388","author":"Willison","year":"2016","journal-title":"Lancet"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"762","DOI":"10.1001\/jamaneurol.2024.1123","article-title":"Expanding clinical spectrum of anti-GQ1b antibody syndrome","volume":"81","author":"Lee","year":"2024","journal-title":"JAMA Neurol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4982","DOI":"10.1007\/s00415-024-12410-4","article-title":"Clinical, paraclinical and outcome features of 166 patients with acute anti-GQ1b antibody syndrome","volume":"271","author":"Coly","year":"2024","journal-title":"J. Neurol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"576","DOI":"10.1136\/jnnp-2012-302824","article-title":"Bickerstaff brainstem encephalitis and Fisher syndrome: Anti-GQ1b antibody syndrome","volume":"84","author":"Shahrizaila","year":"2013","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"537","DOI":"10.1038\/nrneurol.2014.138","article-title":"Guillain\u2013Barr\u00e9 and Miller Fisher syndromes\u2014New diagnostic classification","volume":"10","author":"Wakerley","year":"2014","journal-title":"Nat. Rev. Neurol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"674","DOI":"10.1007\/s00415-008-0775-0","article-title":"Bickerstaff\u2019s brainstem encephalitis and Fisher syndrome form a continuous spectrum: Analysis of 581 cases","volume":"255","author":"Ito","year":"2008","journal-title":"J. Neurol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e1085","DOI":"10.1212\/WNL.0000000000008107","article-title":"Acute vestibular syndrome associated with anti-GQ1b antibody","volume":"93","author":"Lee","year":"2019","journal-title":"Neurology"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1212\/01.wnl.0000324266.95814.74","article-title":"Acute ophthalmoplegia (without ataxia) associated with anti-GQ1b antibody","volume":"71","author":"Lee","year":"2008","journal-title":"Neurology"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/S0022-510X(02)00241-1","article-title":"Acute isolated bulbar palsy with anti-GT1a IgG antibody subsequent to Campylobacter jejuni enteritis","volume":"205","author":"Onodera","year":"2002","journal-title":"J. Neurol. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1148","DOI":"10.1136\/jnnp.2007.142950","article-title":"Ganglioside complexes containing GQ1b as targets in Miller Fisher and Guillain-Barr\u00e9 syndromes","volume":"79","author":"Kanzaki","year":"2008","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_12","first-page":"e49866","article-title":"Anti-GQ1b antibody syndrome presented as locked-in syndrome: A rare case report","volume":"15","author":"Williams","year":"2023","journal-title":"Cureus"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Deng, J., Wu, L., Wei, S., and Zhang, X. (2023). Atypical anti-GQ1b antibody syndrome presenting with vomiting as the initial symptom: A case report and literature review. BMC Neurol., 23.","DOI":"10.1186\/s12883-023-03213-7"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Noioso, C.M., Bevilacqua, L., Acerra, G.M., Della Valle, P., Serio, M., Vinciguerra, C., Piscosquito, G., Toriello, A., Barone, P., and Iovino, A. (2023). Miller Fisher syndrome: An updated narrative review. Front. Neurol., 14.","DOI":"10.3389\/fneur.2023.1250774"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1056\/NEJM195607122550201","article-title":"An unusual variant of acute idiopathic polyneuritis (syndrome of ophthalmoplegia, ataxia and areflexia)","volume":"255","author":"Fisher","year":"1956","journal-title":"N. Engl. J. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1911","DOI":"10.1212\/WNL.43.10.1911","article-title":"Serum anti-GQ1b IgG antibody is associated with ophthalmoplegia in Miller Fisher syndrome and Guillain-Barr\u00e9 syndrome: Clinical and immunohistochemical studies","volume":"43","author":"Chiba","year":"1993","journal-title":"Neurology"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"677","DOI":"10.1002\/ana.410310619","article-title":"Serum IgG antibody to ganglioside GQ1b is a possible marker of Miller Fisher syndrome","volume":"31","author":"Chiba","year":"1992","journal-title":"Ann. Neurol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1136\/jnnp.70.1.50","article-title":"Anti-GQ1b IgG antibody syndrome: Clinical and immunological range","volume":"70","author":"Odaka","year":"2001","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"486","DOI":"10.1007\/s00415-022-11394-3","article-title":"Acute comitant strabismus in anti-GQ1b antibody syndrome","volume":"270","author":"Lee","year":"2023","journal-title":"J. Neurol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1605","DOI":"10.1212\/01.WNL.0000160399.08456.7C","article-title":"Antecedent infections in Fisher syndrome: A common pathogenesis of molecular mimicry","volume":"64","author":"Koga","year":"2005","journal-title":"Neurology"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2586","DOI":"10.1016\/j.clinph.2018.09.025","article-title":"The electrodiagnosis of Guillain\u2013Barr\u00e9 syndrome subtypes: Where do we stand?","volume":"129","author":"Uncini","year":"2018","journal-title":"Clin. Neurophysiol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"469","DOI":"10.1038\/nrneurol.2014.121","article-title":"Guillain\u2013Barr\u00e9 syndrome: Pathogenesis, diagnosis, treatment and prognosis","volume":"10","author":"Walgaard","year":"2014","journal-title":"Nat. Rev. Neurol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/S0165-5728(99)00213-1","article-title":"The immunopathogenesis of Miller Fisher syndrome","volume":"100","author":"Willison","year":"1999","journal-title":"J. Neuroimmunol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1136\/jnnp-2011-300309","article-title":"Antiganglioside antibodies are associated with axonal Guillain\u2013Barr\u00e9 syndrome: A Japanese\u2013Italian collaborative study","volume":"83","author":"Sekiguchi","year":"2012","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1007\/s40259-025-00708-2","article-title":"Targeting the Neonatal Fc Receptor in Autoimmune Diseases: Pipeline and Progress","volume":"39","author":"Mester","year":"2025","journal-title":"BioDrugs"},{"key":"ref_26","first-page":"CD004761","article-title":"Treatment for Fisher syndrome, Bickerstaff\u2019s brainstem encephalitis and related disorders","volume":"1","author":"Overell","year":"2007","journal-title":"Cochrane Database Syst. Rev."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2245","DOI":"10.1093\/brain\/awm004","article-title":"Immunotherapy for Guillain\u2013Barr\u00e9 syndrome: A systematic review","volume":"130","author":"Hughes","year":"2007","journal-title":"Brain"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1056\/NEJM199204233261705","article-title":"A randomized trial comparing intravenous immune globulin and plasma exchange in Guillain\u2013Barr\u00e9 syndrome","volume":"326","author":"Schmitz","year":"1992","journal-title":"N. Engl. J. Med."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2110766","DOI":"10.1016\/j.clinph.2025.2110766","article-title":"Utility of the combination of median nerve somatosensory evoked potentials and auditory brainstem responses for diagnosing Bickerstaff brainstem encephalitis","volume":"176","author":"Kanbayashi","year":"2025","journal-title":"Clin. Neurophysiol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1016\/j.clinph.2016.11.009","article-title":"Electrophysiology in Fisher syndrome","volume":"128","author":"Kuwabara","year":"2017","journal-title":"Clin. Neurophysiol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1104","DOI":"10.1212\/WNL.56.8.1104","article-title":"Clinical features and prognosis of Miller Fisher syndrome","volume":"56","author":"Mori","year":"2001","journal-title":"Neurology"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1136\/practneurol-2014-000937","article-title":"Mimics and chameleons in Guillain\u2013Barr\u00e9 and Miller Fisher syndromes","volume":"15","author":"Wakerley","year":"2015","journal-title":"Pract. Neurol."},{"key":"ref_33","first-page":"CD001798","article-title":"Plasma exchange for Guillain\u2013Barr\u00e9 syndrome","volume":"7","author":"Chevret","year":"2012","journal-title":"Cochrane Database Syst. Rev."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1016\/S1474-4422(08)70215-1","article-title":"Clinical features, pathogenesis, and treatment of Guillain\u2013Barr\u00e9 syndrome","volume":"7","author":"Ruts","year":"2008","journal-title":"Lancet Neurol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1136\/jnnp-2013-305397","article-title":"Pharyngeal\u2013cervical\u2013brachial variant of Guillain\u2013Barr\u00e9 syndrome","volume":"85","author":"Wakerley","year":"2014","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1680","DOI":"10.1212\/WNL.0b013e3181e07d14","article-title":"Distinguishing acute-onset CIDP from fluctuating Guillain\u2013Barr\u00e9 syndrome: A prospective study","volume":"74","author":"Ruts","year":"2010","journal-title":"Neurology"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1180","DOI":"10.1016\/S1474-4422(13)70215-1","article-title":"Axonal Guillain\u2013Barr\u00e9 syndrome: Concepts and controversies","volume":"12","author":"Kuwabara","year":"2013","journal-title":"Lancet Neurol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"e70009","DOI":"10.1111\/jns.70009","article-title":"Results From a Phase 1 Study Evaluating the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of ANX005, a C1q Inhibitor, in Patients with Guillain\u2013Barr\u00e9 Syndrome","volume":"30","author":"Mohammad","year":"2025","journal-title":"J. Peripher. Nerv. Syst."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1111\/jns.12209","article-title":"International Guillain-Barr\u00e9 Syndrome Outcome Study: Protocol of a prospective observational cohort study on clinical and biological predictors of disease course and outcome in Guillain-Barr\u00e9 syndrome","volume":"22","author":"Jacobs","year":"2017","journal-title":"J. Peripher. Nerv. Syst."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/2\/801\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T09:48:38Z","timestamp":1768902518000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/2\/801"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,19]]},"references-count":39,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["jcm15020801"],"URL":"https:\/\/doi.org\/10.3390\/jcm15020801","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,19]]}}}