{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T07:50:10Z","timestamp":1787730610943,"version":"build-2784847793"},"reference-count":24,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,8]],"date-time":"2025-11-08T00:00:00Z","timestamp":1762560000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>Pediatric seronegative immune-mediated cerebellar ataxia (IMCA) remains a poorly defined and often under-recognized diagnosis, particularly in young children, where symptoms are frequently misattributed to self-limited post-infectious processes. We report the case of a 2.5-year-old girl who presented with acute-onset ataxia (mSARA score: 14). Cerebrospinal fluid analysis revealed pleocytosis and positive oligoclonal bands, while serial brain imaging and extensive autoantibody panels were unremarkable. However, indirect immunohistochemistry (TIIF\/IHC) demonstrated a positive intracellular signal in cerebellar Purkinje cells, supporting the diagnosis of isolated seronegative IMCA. The patient showed sustained clinical improvement with prolonged corticosteroid therapy (mSARA score: 1). To date, only a few similar cases have been reported in the literature. It remains unclear whether these presentations fall within the spectrum of autoimmune encephalitis (AIE) or represent a distinct pediatric phenotype, potentially expanding the age range of primary autoimmune cerebellar ataxia previously described in adults. We recommend incorporating TIIF\/IHC into the diagnostic workup of both isolated and combined pediatric cerebellar ataxia syndromes to support diagnosis and guide individualized treatment. Additionally, neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) are emerging as promising biomarkers in this context and warrant further investigation.<\/jats:p>","DOI":"10.3390\/children12111513","type":"journal-article","created":{"date-parts":[[2025,11,10]],"date-time":"2025-11-10T08:57:55Z","timestamp":1762765075000},"page":"1513","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Seronegative Immune-Mediated Cerebellar Ataxia in Children: Autoimmune Encephalitis Spectrum Disorder or a Distinct Entity?"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0000-2298","authenticated-orcid":false,"given":"Gontika","family":"Maria","sequence":"first","affiliation":[{"name":"Neurological Department, Penteli\u2019s Children Hospital, 11528 Penteli, Greece"},{"name":"Medical School of National, Kapodistrian University of Athens, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4086-7269","authenticated-orcid":false,"given":"Tsimakidi","family":"Chrysanthi","sequence":"additional","affiliation":[{"name":"Neurological Department, Penteli\u2019s Children Hospital, 11528 Penteli, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Salamou","family":"Eudokia","sequence":"additional","affiliation":[{"name":"Neurological Department, Penteli\u2019s Children Hospital, 11528 Penteli, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-9031-7866","authenticated-orcid":false,"given":"Prattos","family":"Theofanis","sequence":"additional","affiliation":[{"name":"Neurological Department, Penteli\u2019s Children Hospital, 11528 Penteli, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kallias","family":"Nikolaos","sequence":"additional","affiliation":[{"name":"Neurological Department, Penteli\u2019s Children Hospital, 11528 Penteli, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kilidireas","family":"Constantinos","sequence":"additional","affiliation":[{"name":"First Department of Neurology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece"},{"name":"Department of Neurology, Henry Dunant Hospital Center, 11526 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tzartos","family":"John","sequence":"additional","affiliation":[{"name":"Second Department of Neurology, \u201cAttikon\u201d University Hospital, School of Medicine, National, Kapodistrian University of Athens, 12462 Athens, Greece"},{"name":"Tzartos NeuroDiagnostics, 11523 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5290-6531","authenticated-orcid":false,"given":"Gkougka","family":"Dionysia","sequence":"additional","affiliation":[{"name":"Neurological Department, Penteli\u2019s Children Hospital, 11528 Penteli, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"768","DOI":"10.1136\/archdischild-2018-315487","article-title":"Acute ataxia in paediatric emergency departments: A multicentre Italian study","volume":"104","author":"Garone","year":"2019","journal-title":"Arch. 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