Exons deletion of CNKSR2 gene identified in X-linked syndromic intellectual disability.

BACKGROUND: The Houge type of X-linked syndromic mental retardation is an X-linked intellectual disability (XLID) recently recorded in the Online Mendelian Inheritance in Man (OMIM) and only 8 cases have been reported in literature thus far. CASE PRESENTATION: We present two brothers with intractable seizures and syndromic intellectual disability with symptoms consisting of delayed development, intellectual disability, and speech and language delay. The mother was a symptomatic carrier with milder clinical phenotype. Whole exome sequencing identified a small fragment deletion spanning four exons, about 9.5 kilobases (kb) in length in the CNKSR2 gene in the patients. The mutation co-segregation revealed that exon deletions occurred de novo in the proband's mother. CONCLUSION: Although large deletions have been reported, no small deletions have yet been identified. In this case report, we identified a small deletion in the CNKSR2 gene. This study enhances our knowledge of the CNKSR2 gene mutation spectrum and provides further information about the phenotypic characteristics of X-linked syndromic intellectual disability.

Three novel patients with epileptic encephalopathy due to biallelic mutations in the PLCB1 gene.

Biallelic mutations in the PLCB1 gene, encoding for a phospholipase C beta isoform strongly expressed in the brain, have been reported to cause infantile epileptic encephalopathy in only four children to date. We report here three additional patients to delineate the phenotypic and genotypic characteristics of the disease. Our three patients were one sporadic case with an intragenic homozygous deletion and two cousins with the homozygous p.(Arg222*) nonsense variant in PLCB1. These patients had severe to profound intellectual disability, epileptic spasms at age 3-5 months concomitant with developmental arrest or regression, other seizure types and drug-resistant epilepsy. With this report, we expand the clinical, radiologic and electroencephalographic knowledge about the extremely rare PLCB1-related encephalopathy. Since the first report in 2010, the overall number of reported patients with our additional patients is currently limited to seven. All seven patients had epileptic encephalopathy, mainly infantile spasms and 6/7 had profound intellectual disability, with one only being able to walk. Truncal hypotonia was the most frequent neurological sign, sometimes associated with pyramidal and/or extrapyramidal hypertonia of limbs. Microcephaly was inconstant. In conclusion, the phenotypical spectrum of PLCB1-related encephalopathy is relatively narrow, comprises infantile spasms and severe to profound intellectual disability, and does not seem to define a recognizable clinical entity.

Minimizing blood loss in hemispherectomy for hemimegalencephaly in low-weight infants: technical note.

INTRODUCTION: Drug-resistant seizures due to hemimegalencephaly in neonates and infants are a unique surgical and anesthesia challenge. While early surgery in these patients may predict a better seizure control, a lower body weight, limited blood volume, and surgical blood loss may make hemispherectomy prohibitive. METHODS: Two infants (weight, 8.7 kg and 3.7 kg) underwent interhemispheric vertical hemispherotomy with endoscope assistance. In the first case, during the lateral disconnection, excessive bleeding prompted the surgeon to coagulate the lenticulostriate arteries at the origin from the middle cerebral artery to reduce bleeding. In the second infant, the lenticulostriate arteries were coagulated before initiating the lateral disconnection. RESULTS: In both infants, the blood loss from lateral dissection was reduced by coagulation of lenticulostriate arteries. CONCLUSION: The authors suggest that early coagulation of the lenticulostriate arteries is a useful strategy to minimize blood loss in low-weight infants undergoing hemispherotomy.

Anxiety disorders in predominantly African American and Caribbean American adults with intractable epilepsy: The role of perceived epilepsy stigma.

INTRODUCTION: Anxiety disproportionately affects people with epilepsy (PWE) and leads to poor outcomes. Yet, risk factors are not well understood especially among underserved groups. This cross-sectional study aimed to identify epilepsy-specific predictors of anxiety disorders in predominantly African American and Caribbean American PWE. MATERIALS AND METHODS: The prevalence of anxiety disorders was established via diagnostic interview (Mini-International Neuropsychiatric Interview (MINI)). We identified the extent to which aspects of seizure burden (seizure frequency, seizure severity, convulsive vs. nonconvulsive seizures), seizure worry, and perceived epilepsy stigma were associated with anxiety disorder diagnosis. Finally, logistic regression assessed the overall and independent contributions of significant risk factors. RESULTS: There were 60 participants (62% women, 52% African American, 27% Caribbean American, 20% Hispanic/Latino) with an average of 2 seizures per month. Nearly half of the sample (43%) had ≥1 anxiety disorder, with 62% of affected individuals qualifying for agoraphobia. Those with anxiety disorders tended to have convulsive seizures (p = 0.037) and endorsed greater seizure worry (p = 0.012), more general symptoms of anxiety (p = 0.005), and worse perceived epilepsy stigma (p = 0.003). Logistic regression accounted for 28% to 37.6% of the variance in anxiety disorder diagnostic status and correctly classified 73% of cases; however, only perceived epilepsy stigma made a unique contribution. CONCLUSIONS: Anxiety disorders were prevalent in these predominantly African American and Caribbean American PWE. Epilepsy-specific risk factors included convulsive seizures, seizure worry, and perceived epilepsy stigma. Interventions aimed at treating anxiety disorders in diverse PWE may especially benefit from targeting stigma beliefs.

Electroclinical features of epilepsy monosomy 1p36 syndrome and their implications.

OBJECTIVIES: Monosomy 1p36 syndrome is a recognized syndrome with multiple congenital anomalies; medical problems of this syndrome include developmental delay, facial dysmorphisms, hearing loss, short stature, brain anomalies, congenital heart defects. Epilepsy can be another feature but there are few data about the types of seizures and long term prognosis. The aim of this work was to analyse the electroclinical phenotype and the long-term outcome in patients with monosomy 1p36 syndrome and epilepsy. MATERIALS AND METHODS: Data of 22 patients with monosomy 1p36 syndrome and epilepsy were reconstructed by reviewing medical records. For each patient we analysed age at time of diagnosis, first signs of the syndrome, age at seizure onset, seizure type and its frequency, EEG and neuroimaging findings, the response to antiepileptic drugs treatment and clinical outcome up to the last follow-up assessment. RESULTS: Infantile Spasm (IS) represents the most frequent type at epilepsy onset, which occurs in 36.4% of children, and a half of these were associated with hypsarrhythmic electroencephalogram. All patients with IS had persistence of seizures, unlike other patients with different seizures onset. Children with abnormal brain neuroimaging have a greater chance to develop pharmacoresistant epilepsy. CONCLUSION: This syndrome represents a significant cause of IS: these patients, who develop IS, can suffer from pharmacoresistent epilepsy, that is more frequent in children with brain abnormalities.

Quality of life and mood in patients with medically intractable epilepsy treated with targeted responsive neurostimulation.

PURPOSE: The primary efficacy and safety measures from a trial of responsive neurostimulation for focal epilepsy were previously published. In this report, the findings from the same study are presented for quality of life, which was a supportive analysis, and for mood, which was assessed as a secondary safety endpoint. METHODS: The study was a multicenter randomized controlled double-blinded trial of responsive neurostimulation in 191 patients with medically resistant focal epilepsy. During a 4-month postimplant blinded period, patients were randomized to receive responsive stimulation or sham stimulation, after which all patients received responsive neurostimulation in open label to complete 2years. Quality of life (QOL) and mood surveys were administered during the baseline period, at the end of the blinded period, and at year 1 and year 2 of the open label period. RESULTS: The treatment and sham groups did not differ at baseline. Compared with baseline, QOL improved in both groups at the end of the blinded period and also at 1year and 2years, when all patients were treated. At 2years, 44% of patients reported meaningful improvements in QOL, and 16% reported declines. There were no overall adverse changes in mood or in suicidality across the study. Findings were not related to changes in seizures and antiepileptic drugs, and patients with mesial temporal seizure onsets and those with neocortical seizure onsets both experienced improvements in QOL. CONCLUSIONS: Treatment with targeted responsive neurostimulation does not adversely affect QOL or mood and may be associated with improvements in QOL in patients, including those with seizures of either mesial temporal origin or neocortical origin.

Exome sequencing identifies compound heterozygous mutations in C12orf57 in two siblings with severe intellectual disability, hypoplasia of the corpus callosum, chorioretinal coloboma, and intractable seizures.

In patients with genetically heterogeneous disorders such as intellectual disability or epilepsy, exome sequencing is a powerful tool to elucidate the underlying genetic cause. Homozygous and compound heterozygous mutations in C12orf57 have recently been described to cause an autosomal recessive syndromic form of intellectual disability, including agenesis/hypoplasia of the corpus callosum, optic coloboma, and intractable seizures. Here, we report on two siblings from nonconsanguineous parents harboring two compound heterozygous loss-of-function mutations in C12orf57 identified by exome sequencing, including a novel nonsense mutation, and review the patients described in the literature.

Intractable seizures after cranioplasty, a dreadful post-operative complication managed efficiently from Nepal: A case series.

INTRODUCTION AND IMPORTANCE: Cranioplasty is an elective neurosurgical procedure following decompressive craniectomy, often associated with post-operative complications such as hemorrhage, seizures, infection, hydrocephalus, and bone resorption. While seizures post-cranioplasty is not uncommon, Intractable seizures are rare but a dreadful complication following cranioplasty. CASE SUMMARY: A 23 and 17-year-old male underwent decompression craniectomy for traumatic brain injury and subsequently underwent titanium mesh and acrylic cranioplasty respectively, During the post-operative period both patients developed intractable seizures. Initially seizures were refractory to multiple anti-epileptic drugs and benzodiazepine induced coma. Intractable seizures were controlled gradually with few anti-epileptic drugs after the removal of cranioplasty. During 2 years' follow-up, there was no new episode of seizures complained by patients. DISCUSSION: Elective cranioplasty following decompressive craniectomy after traumatic head injury is one of the commonest surgical modality carried out globally as a life saving measure. But post-operative complications following cranioplasty such as wound infection, implant displacement, bone resorption, hydrocephalus, epidural hematoma are the commonest observed complications whereas post-operative seizure is the most dreadful complication needing immediate intervention. Along with it intractable seizure is rarer during post- operative period. CONCLUSION: Intractable seizures post-cranioplasty, though rare, are serious and often linked to cerebral edema from negative pressure drainage and dysregulation of cerebral blood flow. Removing the cranioplasty can restore blood flow regulation, stabilize brain tissue, and resolve seizures. Care providers should be aware of this rare complication and to be counselled the patient and the family before the surgery.

Microsurgical lesionectomy for drug-resistant insular cortex epilepsy in focal cortical dysplasia type IIB: a pediatric case report.

Introduction and importance: Focal cortical dysplasia (FCD) is a significant cause of drug-resistant epilepsy, often necessitating surgical intervention. Type IIb FCD poses challenges due to its strong association with drug-resistant seizures. Effective management involves advanced imaging, intraoperative neurophysiological monitoring, and precise surgical techniques. This case study illustrates these strategies in an 11-year-old female with drug-resistant epilepsy attributed to Type IIb FCD. Case presentation: The patient, an 11-year-old female, had drug-resistant seizures despite various anticonvulsant treatments. Preoperative 3 Tesla (3T) MRI revealed an ill-defined lesion in the right frontal operculum. The surgical team used neuro-navigation for intraoperative guidance and electrocorticography for lesionectomy. Pathology confirmed Type IIb FCD with rare concentric calcifications. Clinical discussion: Drug-resistant seizures in FCD often require surgery when medications fail. This case highlights the importance of comprehensive preoperative evaluations and advanced imaging, such as 3T MRI, to accurately identify lesions. Intraoperative neurophysiological monitoring, including electrocorticography, ensures precise resection of the epileptogenic zone. The unusual finding of concentric calcifications in Type IIb FCD is noteworthy, suggesting the need for further research to understand their impact on the disease. Conclusion: Microsurgical lesionectomy is crucial for managing drug-resistant seizures in Type IIb FCD. Combining advanced imaging with intraoperative monitoring improves surgical precision and outcomes. The rare pathological finding of calcifications highlights the diversity of FCD manifestations, warranting further study. These techniques can significantly enhance seizure control and quality of life in patients with drug-resistant epilepsy.

Efficacy and Safety of Perampanel in Children with Drug-Resistant Focal-Onset Seizures: A Retrospective Review.

BACKGROUND: Epilepsy is one of the most common neurological disorders. Existing antiseizure medications (ASMs) are still unable to control seizures in one-third of these patients, making the discovery of antiseizure therapies with novel mechanisms of action a necessity. AIM OF THE STUDY: This study aimed to determine the safety and efficacy of perampanel (PER) as an adjuvant treatment for children with drug-resistant focal-onset seizures with or without focal to bilateral tonic-clonic seizures. PATIENTS AND METHODS: This is a single-center retrospective study of 38 epileptic pediatric patients, aged 2 to 14, at King Faisal Specialist Hospital and Research Center whose seizures were pharmaco-resistant to more than two antiseizure medications and followed for at least three months after PER adjuvant therapy initiation. Efficacy was assessed by the PER response rate at 3-, 6-, and 12-month follow-up evaluations, and side effects were also reported. RESULTS: Multiple seizure types were reported. Myoclonic seizures were the predominant type of epilepsy in 17 children (44.7%). At 3 months, 6 months, and 12 months of follow-up, approximately 23.4%, 23.4%, and 18.4% of the patients were seizure-free at these time points, respectively. Adverse events were documented in 14 patients (35.7%) and led to the discontinuation of PER in 26.3%, 31.6%, and 36.8% of the studied group at the 3-, 6-, and 12-month follow-ups, respectively. The most common adverse events included dizziness or drowsiness, irritability, gait disturbance, and confusion; however, all were transient, and no serious adverse effects occurred. CONCLUSION: Our findings confirm the therapeutic efficacy of adjunctive PER in the treatment of drug-resistant epilepsy in children. As an adjunctive treatment for epilepsy, perampanel demonstrated sufficient effectiveness and tolerability.

Multiple hippocampal transection for mesial temporal lobe epilepsy: A systematic review.

PURPOSE: Multiple hippocampal transection (MHT) is a surgical technique that offers adequate seizure control with minimal perioperative morbidity. However, there is little evidence available to guide neurosurgeons in selecting this technique for use in appropriate patients. This systematic review analyzes patient-level data associated with MHT for intractable epilepsy, focusing on postoperative seizure control and memory outcomes. METHODS: The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant articles were identified from 3 databases (PubMed, Medline, Embase) up to August 1, 2021. Inclusion criteria were that the majority of patients had received a diagnosis of intractable epilepsy, the article was written in English, MHT was the primary procedure, and patient-level metadata were included. RESULTS: Fifty-nine unique patients who underwent MHT were identified across 11 studies. Ten (17%) of 59 patients underwent MHT alone. Forty-three (75%) of 57 patients who had a follow-up 12 months or longer were seizure free at last follow-up. With respect to postoperative verbal memory retention, 9 of 38 (24%) patient test scores did not change, 14 (37%) decreased, and 16 (42%) increased. With respect to postoperative nonverbal memory retention, 12 of 38 (34%) patient test scores did not change, 13 (34%) decreased, and 13 (33%) increased. CONCLUSION: There are few reported patients analyzed after MHT. Although the neurocognitive benefits of MHT are unproven, this relatively novel technique has shown promise in the management of seizures in patients with intractable epilepsy. However, structured trials assessing MHT in isolation are warranted.

Biomarker profiling of vitamin responsive seizures: a potential tool to detect pediatric seizures of unknown aetiology.

Aim: Certain rare inborn errors of metabolism clinically present with intractable seizures that readily respond to vitamin therapy. If identified early, brain damage due to seizures can be prevented. Methodology: A LC-MS method was developed and validated for the simultaneous quantification of the biomarkers in selected vitamin responsive pediatric seizures from dried blood spots. Results: Application of the validated method to a seizure cohort of 46 patients indicated strong agreement of the method for clinical validity. Reference intervals for these biomarkers in dried blood spots were also determined for the population, after screening 956 neonates. Conclusion: The developed method was seen to be sensitive, linear, accurate and precise for testing vitamin responsive pediatric seizures.

Pharmacoresistant seizures in neurofibromatosis type 1 related to hippocampal sclerosis: Three case presentation and review.

Neurofibromatosis type 1 (NF1) is an autosomal dominantly inherited disorder, with an estimated prevalence of 1 in 3000-4000 people. Seizures occur 4-7% of individuals with NF1, mostly due to associated brain tumors or cortical malformations. Hippocampal sclerosis (HS) in the patients with NF1 has been reported very rarely and only 15 patients were found in review of English literature. We presented here 3 additional patients with NF1 and intractable seizures due to hippocampal sclerosis; in whom one of them underwent epilepsy surgery and he is seizure free for 5 years after right temporal lobectomy.

Nonketotic hyperglycinemia: Clinical range and outcome of a rare neurometabolic disease in a single-center.

BACKGROUND: Nonketotic hyperglycinemia (NKH) is an autosomal recessive severe life-threatening catostrophic metabolic disorder. MATERIALS AND METHODS: The present study was conducted in a tertiary reference center in Turkey for six years period. The accurate diagnosis of six NKH patients was based on clinical history of the patients, neurological examinations, seizure semiology, serial electroencephalography (EEG) recordings, neuroimaging findings, metabolic tests and genetic analysis. RESULTS: The common clinical findings were hypotonia with severe head lag, poor feeding, poor sucking, and intractable seizures. The starting age of the symptoms was between birth and 45 days of age (median: 8 days). The starting age of the seizures was between 30 min of age and 45 days of age (median: 18 days). The age of accurate diagnosis was between 1 month of age and 5.5 months of age (mean: 3.75 ±â€¯1.69 months). The cerebrospinal fluid (CSF) to plasma GLY ratio of the patients was between 0.031 and 0.21 (median: 0.16). The EEG patterns of the patients were suppression-burst, hypsarrhythmia, multifocal epileptic activity, and right centro-occipital epileptic activity on admission. The neuroimaging findings were diffuse hypomyelination, corpus callosum (CC) hypoplasia, CC agenesis and brainstem hypoplasia on the magnetic resonance imaging and glycine peak was evidenced on magnetic resonance spectroscopy. Four of the patients were mutation-positive. CONCLUSIONS: If a child is encephalopathic and/or hypotonic with severe head lag, early evaluation of the EEG records should be made even without a history of clinical seizures. The disease has a heterogenous course and the clinical outcome depends on the mutation type.

Treatment of Epileptic Encephalopathies: Current State of the Art.

Childhood epileptic encephalopathies are age-dependent disorders of the brain whose hallmarks include loss of neurologic function over time, abnormal electroencephalographic findings, and seizures. Ictal and interictal electrographic activity are conjointly thought to be at the root of the often devastating neuropsychological deterioration, which is specific to the maturing brain. The goals of treatment are not only to control seizures, but also to prevent or reverse neurologic loss of function. In general, time is of the essence in diagnosis, and experienced specialists should promptly design a treatment plan. Hormonal and immune therapies are at the forefront of treatment in many cases, with traditional antiepileptic drugs and surgery (when an identifiable lesion is present) playing a limited role. However, gold standard evidence for treatment of epileptic encephalopathies remains limited. Ongoing clinical and basic research may lead to better understanding of these catastrophic conditions and to better and more effective therapies.

Electroclinical features of epilepsy associated with 1p36 deletion syndrome: A review.

1p36 terminal deletion is a recently recognized syndrome with multiple congenital anomalies and intellectual disability. It occurs approximately in 1 out of 5000 to 10,000 live births and is the most common subtelomeric microdeletion observed in human. Medical problems commonly caused by terminal deletions of 1p36 include developmental delay, intellectual disability, seizures, vision problems, hearing loss, short stature, brain anomalies, congenital heart defects, cardiomyopathy, renal anomalies and distinctive facial features. Although the syndrome is considered clinically recognizable, there is significant phenotypic variation among affected individuals. Genotype-phenotype correlation in this syndrome is complicated, because of the similar clinical evidence seen in patients with different deletion sizes. We review 34 scientific articles from 1996 to 2016 that described 315 patients with 1p36 delection syndrome. The aim of this review is to find a correlation between size of the 1p36-deleted segments and the neurological clinical phenotypes with the analysis of electro-clinical patterns associated with chromosomal aberrations, that is a major tool in the identification of epilepsy susceptibility genes. Our finding suggest that developmental delay and early epilepsy are frequent findings in 1p36 deletion syndrome that can contribute to a poor clinical outcome for this reason this syndrome should be searched for in patients presenting with infantile spasms associated with a hypsarrhythmic EEG, particulary if they are combined with dismorphic features, severe hypotonia and developmental delay.

Angiocentric Glioma in an Elderly Patient: Case Report and Review of the Literature.

BACKGROUND: Angiocentric glioma is a very uncommon low-grade tumor, predominantly occurring in pediatric patients, that was first described in 2005 and was codified 2 years later as a new central nervous system primary tumor. We herein report an exceptionally rare case of an elderly patient with angiocentric glioma. Only one additional case of angiocentric glioma in a patient older than 65 years has been hitherto reported. CASE DESCRIPTION: An 83-year-old male patient presented at our institution complaining of a 1-month history of progressive weakness of his right hand and difficulty performing fine movements. Magnetic resonance imaging of the brain was performed, and fluid-attenuated inversion recovery and T2-hyperintense diffuse cortico-subcortical lesion were reported. A neuronavigation-guided frontal craniotomy was performed to expose the premotor cortex, motor cortex, Rolandic sulcus, and postcentral gyrus. Intraoperative mapping showed that the tumor was close to the shoulder area. Therefore, only partial resection was safely feasible. Pathology report described astrocytic neoplastic cells affecting mainly the cortex and piamater with the classic finding of subpial palisading, with no endothelial invasion or atypia. Neoplastic cells were positive for glial fibrillary acidic protein, epithelial membrane antigen, Wilms tumor protein-1, P16, and P53. Low proliferative activity was seen (Ki-67 < 2%). Abundant gliovascular structures were also reported. CONCLUSIONS: Considering the morphologic and immunohistochemical data, the final pathologic diagnosis was angiocentric glioma. Furthermore, a thorough review of the literature was performed with the purpose of updating and summarizing the main clinical, radiologic, and pathologic features of this rare tumor.

The first report of Japanese patients with asparagine synthetase deficiency.

BACKGROUND: Asparagine synthetase (ASNS) deficiency was recently discovered as a metabolic disorder of non-essential amino acids, and presents as severe progressive microcephaly, intellectual disorder, dyskinetic quadriplegia, and intractable seizures. METHODS: Two Japanese children with progressive microcephaly born to unrelated patients were analyzed by whole exome sequencing and novel ASNS mutations were identified. The effects of the ASNS mutations were analyzed by structural evaluation and in silico predictions. RESULTS: We describe the first known Japanese patients with ASNS deficiency. Their clinical manifestations were very similar to reported cases of ASNS deficiency. Progressive microcephaly was noted during the prenatal period in patient 1 but only after birth in patient 2. Both patients had novel ASNS mutations: patient 1 had p.L145S transmitted from his mother and p.L247W which was absent from his mother, while patient 2 carried p.V489D and p.W541Cfs*5, which were transmitted from his mother and father, respectively. Three of the four mutations were predicted to affect protein folding, and in silico analyses suggested that they would be pathogenic. CONCLUSION: We report the first two Japanese patients with ASNS deficiency. Disease severity appears to vary among patients, as is the case for other non-essential amino acid metabolic disorders.

Clinical, imaging, and immunohistochemical characteristics of focal cortical dysplasia Type II extratemporal epilepsies in children: analyses of an institutional case series.

OBJECTIVE Focal cortical dysplasia (FCD) Type II is divided into 2 subgroups based on the absence (IIA) or presence (IIB) of balloon cells. In particular, extratemporal FCD Type IIA and IIB is not completely understood in terms of clinical, imaging, biological, and neuropathological differences. The aim of the authors was to analyze distinctions between these 2 formal entities and address clinical, MRI, and immunohistochemical features of extratemporal epilepsies in children. METHODS Cases formerly classified as Palmini FCD Type II nontemporal epilepsies were identified through the prospectively maintained epilepsy database at the British Columbia Children's Hospital in Vancouver, Canada. Clinical data, including age of seizure onset, age at surgery, seizure type(s) and frequency, affected brain region(s), intraoperative electrocorticographic findings, and outcome defined by Engel's classification were obtained for each patient. Preoperative and postoperative MRI results were reevaluated. H & E-stained tissue sections were reevaluated by using the 2011 International League Against Epilepsy classification system and additional immunostaining for standard cellular markers (neuronal nuclei, neurofilament, glial fibrillary acidic protein, CD68). Two additional established markers of pathology in epilepsy resection, namely, CD34 and α-B crystallin, were applied. RESULTS Seven nontemporal FCD Type IIA and 7 Type B cases were included. Patients with FCD Type IIA presented with an earlier age of epilepsy onset and slightly better Engel outcome. Radiology distinguished FCD Types IIA and IIB, in that Type IIB presented more frequently with characteristic cortical alterations. Nonphosphorylated neurofilament protein staining confirmed dysplastic cells in dyslaminated areas. The white-gray matter junction was focally blurred in patients with FCD Type IIB. α-B crystallin highlighted glial cells in the white matter and subpial layer with either of the 2 FCD Type II subtypes and balloon cells in patients with FCD Type IIB. α-B crystallin positivity proved to be a valuable tool for confirming the histological diagnosis of FCD Type IIB in specimens with rare balloon cells or difficult section orientation. Distinct nonendothelial cellular CD34 staining was found exclusively in tissue from patients with MRI-positive FCD Type IIB. CONCLUSIONS Extratemporal FCD Types IIA and IIB in the pediatric age group exhibited imaging and immunohistochemical characteristics; cellular immunoreactivity to CD34 emerged as an especially potential surrogate marker for lesional FCD Type IIB, providing additional evidence that FCD Types IIA and IIB might differ in their etiology and biology. Although the sample number in this study was small, the results further support the theory that postoperative outcome-defined by Engel's classification-is multifactorial and determined by not only histology but also the extent of the initial lesion, its location in eloquent areas, intraoperative electrocorticographic findings, and achieved resection grade.

Endoscopic posterior interhemispheric complete corpus callosotomy.

Traditionally corpus callosotomy is done through a craniotomy centered at the coronal suture, with the aid of a microscope. This involves dissecting through the interhemispheric fissure below the falx to reach the corpus callosum. The authors describe a posterior interhemispheric approach to complete corpus callosotomy with an endoscope, which bypasses the need to perform interhemispheric dissection because the falx is generally close to the corpus callosum in this region.