Broadening the scope of multigene panel analysis for adult epilepsy patients.

OBJECTIVE: Epilepsy is a suitable target for gene panel sequencing because a considerable portion of epilepsy is now explained by genetic components, especially in syndromic cases. However, previous gene panel studies on epilepsy have mostly focused on pediatric patients. METHODS: We enrolled adult epilepsy patients meeting any of the following criteria: family history of epilepsy, seizure onset age ≤ 19 years, neuronal migration disorder, and seizure freedom not achieved by dual anti-seizure medications. We sequenced the exonic regions of 211 epilepsy genes in these patients. To confirm the pathogenicity of a novel MTOR truncating variant, we electroporated vectors with different MTOR variants into developing mouse brains. RESULTS: A total of 92 probands and 4 affected relatives were tested, and the proportion of intellectual disability (ID) and/or developmental disability (DD) was 21.7%. As a result, twelve probands (13.0%) had pathogenic or likely pathogenic variants in the following genes or regions: DEPDC5, 15q12-q13 duplication (n = 2), SLC6A1, SYNGAP1, EEF1A2, LGI1, MTOR, KCNQ2, MEF2C, and TSC1 (n = 1). We confirmed the functional impact of a novel truncating mutation in the MTOR gene (c.7570C > T, p.Gln2524Ter) that disrupted neuronal migration in a mouse model. The diagnostic yield was higher in patients with ID/DD or childhood-onset seizures. We also identified additional candidate variants in 20 patients that could be reassessed by further studies. SIGNIFICANCE: Our findings underscore the clinical utility of gene panel sequencing in adult epilepsy patients suspected of having genetic etiology, especially those with ID/DD or early-onset seizures. Gene panel sequencing could not only lead to genetic diagnosis in a substantial portion of adult epilepsy patients but also inform more precise therapeutic decisions based on their genetic background. PLAIN LANGUAGE SUMMARY: This study demonstrated the effectiveness of gene panel sequencing in adults with epilepsy, revealing pathogenic or likely pathogenic variants in 13.0% of patients. Higher diagnostic yields were observed in those with neurodevelopmental disorders or childhood-onset seizures. Additionally, we have shown that expanding genetic studies into adult patients would uncover new types of pathogenic variants for epilepsy, contributing to the advancement of precision medicine for individuals with epilepsy. In conclusion, our results highlight the practical value of employing gene panel sequencing in adult epilepsy patients, particularly when genetic etiology is clinically suspected.

Prevalence and Characterization of NOTCH2NLC GGC Repeat Expansions in Koreans: From a Hospital Cohort Analysis to a Population-Wide Study.

Background and Objectives: GGC repeat expansions in the NOTCH2NLC gene are associated with a broad spectrum of progressive neurologic disorders, notably, neuronal intranuclear inclusion disease (NIID). We aimed to investigate the population-wide prevalence and clinical manifestations of NOTCH2NLC-related disorders in Koreans. Methods: We conducted a study using 2 different cohorts from the Korean population. Patients with available brain MRI scans from Seoul National University Hospital (SNUH) were thoroughly reviewed, and NIID-suspected patients presenting the zigzag edging signs underwent genetic evaluation for NOTCH2NLC repeats by Cas9-mediated nanopore sequencing. In addition, we analyzed whole-genome sequencing data from 3,887 individuals in the Korea Biobank cohort to estimate the distribution of the repeat counts in Koreans and to identify putative patients with expanded alleles and neurologic phenotypes. Results: In the SNUH cohort, among 90 adult-onset leukoencephalopathy patients with unknown etiologies, we found 20 patients with zigzag edging signs. Except for 2 diagnosed with fragile X-associated tremor/ataxia syndrome and 2 with unavailable samples, all 16 patients (17.8%) were diagnosed with NIID (repeat range: 87-217). By analyzing the Korea Biobank cohort, we estimated the distribution of repeat counts and threshold (>64) for Koreans, identifying 6 potential patients with NIID. Furthermore, long-read sequencing enabled the elucidation of transmission and epigenetic patterns of NOTCH2NLC repeats within a family affected by pediatric-onset NIID. Discussion: This study presents the population-wide distribution of NOTCH2NLC repeats and the estimated prevalence of NIID in Koreans, providing valuable insights into the association between repeat counts and disease manifestations in diverse neurologic disorders.

Chronic social stress in early life can predispose mice to antisocial maltreating behavior.

Purpose: In our previous study, we developed an assay system to evaluate antisocial maltreating behavior of conspecific mice using a perpetrator-victim paradigm. We also generated a mouse model for the maltreating behavior by mimicking child maltreatment or abuse. Here, we further investigate the antisocial behavior using anti-aggressive and antipsychotic drugs. Methods: Model mice sequentially subjected to maternal separation (MS), social defeat (SD), and social isolation (SI) in that order (MS/SD/SI model) were subjected to a maltreating behavioral task. The MS/SD/SI mice were treated with oxytocin (OXY), clozapine (CLZ), haloperidol (HAL), and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Western blotting and enzyme-linked immunosorbent assay were used for protein analysis. Results: A substantial portion of the MS/SD/SI model mice (46% of males and 40% of females) showed a higher number of nose pokes than the control. OXY or 8-OH-DPAT treatment reduced the high number of nose pokes by the MS/SD/SI mice, whereas HAL increased it. CLZ did not affect the number of nose pokes by the MS/SD/SI mice. Interestingly, although the OXY level in the MS/SD/SI mice was similar to that in the control, the amount of OXY receptor was lower in the MS/SD/SI mice. The amount of 5-HT1A receptor was also decreased in the MS/SD/SI mice. Conclusion: Chronic social stress in childhood might predispose a mouse to antisocial behavior. Our maltreating behavior assay system, including the MS/SD/SI model, is a good animal system for research on and drug screening for brain disorders associated with antisocial or psychotic behavior.

Eosinophilic meningoencephalitis successfully treated with glucocorticoids and intravenous immunoglobulin: a case report.

Eosinophilic meningoencephalitis is a rare inflammatory condition of the central nervous system. As a limited number of cases has been reported, debate remains on the optimal treatment. We present a case of idiopathic eosinophilic meningoencephalitis successfully treated with glucocorticoids and intravenous immunoglobulin (IVIG). After extensive evaluation to rule out other possible causes, the patient was treated with intravenous (IV) dexamethasone and showed significant improvement within a few days. However, neurologic impairment persisted, and follow-up lumbar puncture results showed only a mild decrease in pleocytosis. Even after an additional 5 days of IV methylprednisolone, cerebrospinal fluid (CSF) pleocytosis persisted, and brain magnetic resonance imaging (MRI) showed an increase in enhanced lesions, implying persistent neuroinflammation. The patient was maintained on high-dose oral prednisolone for 2 months, and additional immune-modulatory effects were treated with IVIG. Follow-up MRI at 2 months showed a significant decrease in the extent of multiple enhanced lesions and a normalized CSF profile. The patient was maintained on regular maintenance doses of IVIG for an additional 6 months without any neurologic signs or symptoms. Inflammation is the key pathophysiology underlying neurological damage in eosinophilic meningoencephalitis. A literature review revealed that corticosteroid treatment is the only anti-inflammatory treatment used in cases of idiopathic meningoencephalitis, resulting in sufficient response in most patients but only partial response or death in a few cases. This is the first case report of IVIG use in idiopathic eosinophilic meningoencephalitis, suggesting the possibility of a new treatment modality for refractory cases.

Gut microbiome diversity in a febrile seizure mouse model.

Purpose: Febrile seizures at a young age can provoke late-onset temporal lobe epilepsy. Since recent evidence has suggested that the gut microbiome affects central nervous system pathology across the blood-brain barrier, we hypothesized that febrile seizures alter the composition of the gut microbiome to provoke epilepsy. Methods: Third-generation C57BL/6 mice were separated into two groups (n = 5 each), and hot air was applied to only one group to cause febrile seizures. After two weeks of heat challenge, the fecal pellets acquired from each group were analyzed. Results: The gut microbiota of fecal pellets from each group revealed five taxa at the genus level and eight taxa at the species level that were significantly different in proportion between the groups. Conclusion: Although there was no significant difference in the overall diversity of the gut microbiota between the two groups, the identified heterogeneity may imply the pathognomonic causative relevance of febrile seizures and the development of epilepsy.

Topiramate dosage optimization for effective antiseizure management via population pharmacokinetic modeling.

OBJECTIVE: Despite the suggested topiramate serum level of 5-20 mg/L, numerous institutions have observed substantial drug response at lower levels. We aim to investigate the correlation between topiramate serum levels, drug responsiveness, and adverse events to establish a more accurate and tailored therapeutic range. METHODS: We retrospectively analyzed clinical data collected between January 2017 and January 2022 at Seoul National University Hospital. Drug responses to topiramate were categorized as "insufficient" or "sufficient" by reduction in seizure frequency ≥ 50%. A population pharmacokinetic model estimated serum levels from spot measurements. ROC curve analysis determined the optimal cutoff values. RESULTS: A total of 389 epilepsy patients were reviewed having a mean dose of 178.4 ± 117.9 mg/day and the serum level, 3.9 ± 2.8 mg/L. Only 5.6% samples exhibited insufficient response, with a mean serum level of 3.6 ± 2.5 mg/L while 94.4% demonstrated sufficient response, with a mean 4.0 ± 2.8 mg/L, having no statistical significance. Among the 69 reported adverse events, logistic regression analysis identified a significant association between ataxia and serum concentration (p = 0.04), with an optimal cutoff value of 6.5 mg/L. INTERPRETATION: This study proposed an optimal therapeutic concentration for topiramate based on patients' responsiveness to the drug and the incidence of adverse effects. We recommended serum levels below 6.5 mg/L to mitigate the risk of ataxia-related side effects while dose elevation was found unnecessary for suboptimal responders, as the drug's effectiveness plateaus at minimal doses.

Teratoma pathology and genomics in anti-NMDA receptor encephalitis.

INTRODUCTION: Ovarian teratoma is a common occurrence in patients with anti-NMDA receptor encephalitis (NMDARe), and its removal is crucial for a favorable prognosis. However, the initial pathogenesis of autoimmunity in the encephalitic teratoma remains unclear. In this study, we aimed to investigate the genomic landscape and microscopic findings by comparing NMDARe-associated teratomas and non-encephalitic control teratomas. MATERIALS AND METHODS: A prospective consecutive cohort of 84 patients with NMDARe was recruited from January 2014 to April 2020, and among them, patients who received teratoma removal surgery at Seoul National University Hospital were enrolled. We conducted a comparison of whole-exome sequencing data and pathologic findings between NMDARe-associated teratomas and control teratomas. RESULTS: We found 18 NMDARe-associated teratomas from 15 patients and compared them with 17 non-encephalitic control teratomas. Interestingly, the genomic analysis revealed no significant differences in mutations between encephalitic and non-encephalitic teratomas. Pathologic analysis showed no discrepancies in terms of the presence of neuronal tissue and lymphocytic infiltration between the encephalitic teratomas (n = 14) and non-encephalitic teratomas (n = 18). However, rituximab-naïve encephalitic teratomas exhibited a higher frequency of germinal center formation compared to non-encephalitic teratomas (80% vs. 16.7%, P = 0.017). Additionally, rituximab-treated encephalitic teratomas demonstrated a reduced number of CD20+ cells and germinal centers in comparison to rituximab-naïve encephalitic teratomas (P = 0.048 and 0.023, respectively). DISCUSSION: These results suggest that the initiation of immunopathogenesis in NMDARe-associated teratoma is not primarily attributed to intrinsic tumor mutations, but rather to immune factors present in the encephalitic patient group, ultimately leading to germinal center formation within the teratoma.

Using spectral and temporal filters with EEG signal to predict the temporal lobe epilepsy outcome after antiseizure medication via machine learning.

Epilepsy is a neurological disorder in which the brain is transiently altered. Predicting outcomes in epilepsy is essential for providing feedback that can foster improved outcomes in the future. This study aimed to investigate whether applying spectral and temporal filters to resting-state electroencephalography (EEG) signals could improve the prediction of outcomes for patients taking antiseizure medication to treat temporal lobe epilepsy (TLE). We collected EEG data from a total of 46 patients (divided into a seizure-free group (SF, n = 22) and a non-seizure-free group (NSF, n = 24)) with TLE and retrospectively reviewed their clinical data. We segmented spectral and temporal ranges with various time-domain features (Hjorth parameters, statistical parameters, energy, zero-crossing rate, inter-channel correlation, inter-channel phase locking value and spectral information derived from Fourier transform, Stockwell transform, and wavelet transform) and compared their performance by applying an optimal frequency strategy, an optimal duration strategy, and a combination strategy. For all time-domain features, the optimal frequency and time combination strategy showed the highest performance in distinguishing SF patients from NSF patients (area under the curve (AUC) = 0.790 ± 0.159). Furthermore, optimal performance was achieved by utilizing a feature vector derived from statistical parameters within the 39- to 41-Hz frequency band with a window length of 210 s, as evidenced by an AUC of 0.748. By identifying the optimal parameters, we improved the performance of the prediction model. These parameters can serve as standard parameters for predicting outcomes based on resting-state EEG signals.

Identification of bacterial pathogens in brain abscesses by metagenomic approach using nanopore 16S amplicon sequencing.

Brain abscess is medically challenging. In this study, we applied nanopore sequencing for 16S rRNA analysis and investigated its efficacy and diagnostic value for patients with brain abscesses. Genomic DNA was extracted from the pus samples (n = 27) of brain abscess, and 16S rRNA genes were amplified by PCR. Sequencing libraries were generated using a rapid barcoding kit, and the generated reads were analyzed using the EPI2ME16S workflow. A conventional culture study was performed. More sensitive identification of pathogens was made by 16S sequencing, faster than the culture study. The proportion of anaerobic bacteria identified by 16S sequencing was higher (75%) than that obtained by culturing (32%). Polymicrobial infections were identified in 10 cases (40%) by 16S sequencing, while the culture study identified multiple bacteria in only 2 cases (8%). 16S sequencing was useful for identifying the composition of polymicrobial infections, including rare pathogens, and for the initial diagnosis of space-occupying lesions.

Myelin oligodendrocyte glycoprotein antibody-associated encephalitis after severe acute respiratory syndrome coronavirus 2 infection: a case report and retrospective case reviews.

Several cases of myelin oligodendrocyte glycoprotein (MOG) antibody-associated encephalitis have been reported after coronavirus disease 2019 (COVID-19). In this case, the patient presented with focal status epilepticus with impaired awareness, auditory hallucinations, and incoherent speech after COVID-19. Brain magnetic resonance imaging revealed no specific findings. Cerebrospinal fluid results showed pleocytosis and MOG antibody testing confirmed anti-MOG antibody with live cell-based fluorescence-activated cell sorting assay. The patient was diagnosed with MOG antibody-associated autoimmune encephalitis and treated with intravenous immunoglobulin, rituximab, and tocilizumab. This case occurred presumably due to auto-antibody production following COVID-19.

Autoimmune limbic encephalitis combined with leptomeningeal metastases of non-small cell lung cancer: treatment response to osimertinib, immunoglobulin, rituximab, and tocilizumab.

When a patient with encephalopathy has an organic brain lesion, his symptom is easily and often mistakenly attributed to that brain lesion. However, a combination of different conditions is also possible. We present a case of autoimmune limbic encephalitis combined with leptomeningeal carcinomatosis. A 57-year-old female patient was transferred to our institute with a 1-month history of seizure and aggressive behavior. Subacute onset of psychosis with multifocal T2 high signal lesions suggested autoimmune encephalitis, and high-dose steroid pulse and immunoglobulin therapy were started. However, a cerebrospinal fluid study revealed metastatic adenocarcinoma of non-small cell lung cancer, of which she was in complete remission state. Osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor, was started targeting leptomeningeal metastases while maintaining immunotherapy of rituximab and tocilizumab. Her neurological symptoms showed improvement in response to immunotherapy which lasted approximately 1 month and then deteriorated again. We concluded that her symptoms were more attributable to autoimmune encephalitis than leptomeningeal carcinomatosis, and discontinued osimertinib.

Five-Year Retention of Perampanel and Polytherapy Patterns: 328 Patients From a Single Center in South Korea.

BACKGROUND AND PURPOSE: Perampanel (PER) is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid antagonist used to treat focal and generalized epilepsy. Comprehensive data from real-world settings with long-term follow-ups are still scarce. This study aimed to determine the factors related to PER retention and the polytherapy pattern with PER. METHODS: We reviewed all patients with epilepsy with a history of PER prescription during 2008-2017 and over a follow-up of >3 years. PER usage patterns and associated factors were analyzed. RESULTS: Among the 2,655 patients in the cohort, 328 (150 females, 178 males) were enrolled. The ages at onset and diagnosis were 21.1±14.7 years and 25.6±16.1 years (mean±standard deviation), respectively. The age at the first visit to our center was 31.8±13.8 years. Seizure types were focal, generalized, and unknown onset in 83.8%, 15.9%, and 0.3% of patients, respectively. The most common etiology was structural (n=109, 33.2%). The maintenance duration of PER was 22.6±19.2 months (range=1-66 months). The initial number of concomitant antiseizure medications was 2.4±1.4 (range=0-9). The most common regimen was PER plus levetiracetam (n=41, 12.5%). The median number of 1-year seizures before PER usage was 8 (range=0-1,400). A seizure reduction of >50% was recorded in 34.7% of patients (52.0% and 29.2% in generalized and focal seizures, respectively). The 1-, 2-, 3-, 4-, and 5-year retention rates for PER were 65.3%, 50.4%, 40.4%, 35.3%, and 21.5%, respectively. A multivariate analysis indicated that lower age at onset was associated with longer retention (p=0.01). CONCLUSIONS: PER was safely used in patients with diverse characteristics and was maintained for a long time in a real-world setting, especially in patients with a lower age at onset.

Talaromyces rugulosus ventriculitis diagnosed by nanopore amplicon sequencing, 2022.

Ventriculitis has serious complications and a high mortality rate, so it is important to early identification of the pathogen for appropriate treatment. We report case of ventriculitis caused by Talaromyces rugulosus, a rare pathogen, in South Korea. Affected patient was immunocompromised. Repeated cerebrospinal fluid culture tests were negative, but the pathogen was identified by fungal internal transcribed spacer amplicon nanopore sequencing. The pathogen was detected outside the endemic area of talaromycosis.

Lesion Detection Through MRI Postprocessing in Pathology-Proven Focal Cortical Dysplasia: Experience at a Single Institution in the Republic of Korea.

BACKGROUND AND PURPOSE: Focal cortical dysplasia (FCD) is one of the most common causes of drug-resistant epilepsy, and necessitates a multimodal evaluation to ensure optimal surgical treatment. This study aimed to determine the supportive value of the morphometric analysis program (MAP) in detecting FCD using data from a single institution in Korea. METHODS: To develop a standard reference for the MAP, normal-looking MRIs by two scanners that are frequently used in this center were chosen. Patients with drug-resistant epilepsy and FCD after surgery were candidates for the analysis. The three-dimensional T1-weighted MRI scans of the patients were analyzed as test cases using the MAP. RESULTS: The MRI scans of 87 patients were included in the analysis. The radiologist detected abnormal findings correlated with FCD (RAD positive [RAD(+)]) in 34 cases (39.1%), while the MAP could detect FCD in 25.3% of cases. A combination of the MAP (MAP[+] cases) with interpretations by the radiologist increased the detection to 42.5% (37 cases). The lesion detection rate was not different according to the type of reference scanners except in one case. MAP(+)/RAD(-) presented in three cases, all of which had FCD type IIa. The detection rate was slightly higher using the same kind of scanner as a reference, but not significantly (35.0% vs. 22.4% p=0.26). CONCLUSIONS: The results of postprocessing in the MAP for detecting FCD did not depend on the type of reference scanner, and the MAP was the strongest in detecting FCD IIa. We suggested that the MAP could be widely utilized without developing institutional standards and could become an effective tool for detecting FCD lesions.

Clinicoradiologic data of familial cerebral cavernous malformation with age-related disease burden.

OBJECTIVE: Familial cerebral cavernous malformation (FCCM) is an autosomal dominant disease induced by loss-of-function mutations in three CCM genes, KRIT1, CCM2, and PDCD10. However, previous studies paid little attention to analyzing the radiologic features and age-related disease burden according to the genes. Therefore, we retrospectively reviewed the genetic tests of our center's clinical FCCM patients. METHOD: This study investigated clinical FCCM patients with multiple lesions or a family history of CCMs who underwent the FCCM gene (KRTI1, CCM2, and PDCD10) panel test. The clinical, genetic, and radiologic features were analyzed. RESULT: Among the patients (n = 34) undergoing the FCCM gene test, twenty-seven patients had CCM confirmed by brain MRI, and twenty-one patients were considered to have FCCM (cohort 1). In cohort 1, thirteen patients had mutations in the FCCM gene, but eight did not. Cohort 2 comprised cohort 1 and four family members with the same mutation as the probands. Six novel variants in CCM genes were detected (KRIT1 c.22_26del, c.815dup, c.1094_1098del, c.1147-2A>G, c.2124dup, and PDCD10 c.150 + 1dup). Cohort 1 demonstrated that brainstem lesions were mostly associated with the mutation detection in CCM genes (brainstem, lateral temporal, and parietal lesions vs. lateral temporal and parietal lesions, AUC 0.928 vs. 0.779, P = 0.0389). The radiologic severity worsened according to age in the KRIT1 group compared with the Mutation not detected group (correlation coefficient 0.75 (P < 0.001) versus 0.53 (P = 0.004)). CONCLUSION: The brainstem lesion could be the radiologic marker for FCCM with the mutation detected. The age-related disease burden regarding FCCM according to genetic information was demonstrated.

MOG antibody-associated encephalitis in adult: clinical phenotypes and outcomes.

BACKGROUND: We investigated the clinical characteristics and outcomes of myelin oligodendrocyte glycoprotein (MOG) antibody-associated autoimmune encephalitis (MOGAE) in adult patients. METHODS: From an institutional cohort, we analysed adult patients with MOGAE followed-up for more than 1 year. Disease severity was assessed using the modified Rankin scale (mRS) and Clinical Assessment Scale in Autoimmune Encephalitis scores. Immunotherapy profiles, outcomes and disease relapses were evaluated along with serial brain MRI data. RESULTS: A total of 40 patients were enrolled and categorised into cortical encephalitis (18 patients), limbic encephalitis (LE, 5 patients) and acute disseminated encephalomyelitis (ADEM, 17 patients). 80.0% of patients achieved good clinical outcomes (mRS 0‒2) and 40.0% relapsed. The LE subtype was associated with an older onset age (p=0.004) and poor clinical outcomes (p=0.014) than the other subtypes but with a low rate of relapse (0.0%). 21/25 (84.0%) relapse attacks were associated with an absence or short (≤6 months) immunotherapy maintenance. On MRI, the development of either diffuse cerebral or medial temporal atrophy within the first 6 month was correlated with poor outcomes. MOG-antibody (MOG-Ab) was copresent with anti-N-methyl-D-aspartate receptor (NMDAR)-antibody in 13 patients, in whom atypical clinical presentation (cortical encephalitis or ADEM, p<0.001) and disease relapse (46.2% vs 0.0%, p<0.001) were more frequent compared with conventional NMDAR encephalitis without MOG-Ab. CONCLUSIONS: Outcomes are different according to the three phenotypes in MOGAE. Short immunotherapy maintenance is associated with relapse, and brain atrophy was associated with poor outcomes. Patients with dual antibodies of NMDAR and MOG have a high relapse rate.