Case of Limbic Encephalitis with Positive Anti-Sry-like High Mobility Group Box (SOX) 1 Antibody
Marelisa Albelo Martinez1, Jonathan Cahill1, Syed Rizvi1
1Clinical Multiple Sclerosis Fellowship at Rhode Island Hospital and the Warren Alpert Medical School of Brown University
Objective:
To report a rare presentation of limbic encephalitis associated with positive SOX 1 antibody.
Background:
Anti-SOX 1 antibodies are under-characterized onconeural autoantibodies that have been associated with paraneoplastic syndromes like Lambert- Eaton Myasthenic Syndrome and Cerebellar Degeneration. There have also been rare cases of Paraneoplastic Limbic Encephalitis reported.
Results:
77-year-old female with history of alcoholic cirrhosis initially had subacute behavioral changes and right-handed tremor in June 2023. In December 2023, was found lethargic with left sided weakness and left gaze deviation. EEGs showed lateralized epileptiform discharges in the right hemisphere and electrographic status epilepticus. Brain MRI showed right temporal lobe, thalamus, and insula hyperintensity with diffusion restriction. She was treated empirically for HSV encephalitis, but behavioral changes persisted. In March 2024, she had recurrence of status epilepticus and fever. CSF showed 600 WBC (88 neutrophils), protein 69, glucose 64, negative culture and HSV titers. She was treated for bacterial meningitis. By June 2024, patient continued with cognitive and functional decline, needing 3 antiseizure medications. CSF had 200 WBC, protein 41, and glucose 61 with negative culture. Serum anti-SOX-1 antibody was positive. Antibodies including anti-amphiphysin, AMPA, DPPX, CV2, LG1, CASPR2, GABABR/GABAAR, PCCA/ANNA, Purkinje Cell, mGLUR1, GAD 65, NMDAR, were negative in CSF and serum. Whole-body pet scan showed intense FDG uptake within the mesial right temporal lobe. No evidence of malignancy. Patient received 5 days of immunoglobulin (IVIG) and steroids in July 2024. Since this treatment, continues to show improvement in cognition and has been seizure free even after simplification of antiseizure regimen. Patient will continue IVIG therapy and routine monitoring for underlying malignancy.
Conclusions:
The neurological presentations of patients with anti-SOX1 abs are more diverse than recognized, leading to potential misdiagnosis as infectious or neurodegenerative disorders. Continued reporting of cases is warranted to increase the awareness of the full spectrum of presentations.
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