Genetic regulation of gene expression in the epileptic human hippocampus.

Epilepsy is a serious and common neurological disorder. Expression quantitative loci (eQTL) analysis is a vital aid for the identification and interpretation of disease-risk loci. Many eQTLs operate in a tissue- and condition-specific manner. We have performed the first genome-wide cis-eQTL analysis of human hippocampal tissue to include not only normal (n = 22) but also epileptic (n = 22) samples. We demonstrate that disease-associated variants from an epilepsy GWAS meta-analysis and a febrile seizures (FS) GWAS are significantly more enriched with epilepsy-eQTLs than with normal hippocampal eQTLs from two larger independent published studies. In contrast, GWAS meta-analyses of two other brain diseases associated with hippocampal pathology (Alzheimer's disease and schizophrenia) are more enriched with normal hippocampal eQTLs than with epilepsy-eQTLs. These observations suggest that an eQTL analysis that includes disease-affected brain tissue is advantageous for detecting additional risk SNPs for the afflicting and closely related disorders, but not for distinct diseases affecting the same brain regions. We also show that epilepsy eQTLs are enriched within epilepsy-causing genes: an epilepsy cis-gene is significantly more likely to be a causal gene for a Mendelian epilepsy syndrome than to be a causal gene for another Mendelian disorder. Epilepsy cis-genes, compared to normal hippocampal cis-genes, are more enriched within epilepsy-causing genes. Hence, we utilize the epilepsy eQTL data for the functional interpretation of epilepsy disease-risk variants and, thereby, highlight novel potential causal genes for sporadic epilepsy. In conclusion, an epilepsy-eQTL analysis is superior to normal hippocampal tissue eQTL analyses for identifying the variants and genes underlying epilepsy.

Correction to: Open resection of hypothalamic hamartomas for intractable epilepsy revisited, using intraoperative MRI.

The authors apologize to have sent a final manuscript draft omitting "Athanasius Chawira" from the list of authors. The correct list of authors is given in this article.The original article has been corrected.

Open resection of hypothalamic hamartomas for intractable epilepsy revisited, using intraoperative MRI.

INTRODUCTION: Hypothalamic hamartomas (HHs) are rare non-neoplastic lesions which cause drug-resistant epilepsy with associated behavioural, psychiatric and endocrine issues. With the development of new minimally invasive techniques for the treatment of HH, there is a need to reappraise the effectiveness and safety of each approach. We review the outcomes of HH patients treated surgically, utilizing intraoperative magnetic resonance imaging (IOMRI), by a team of Alder Hey NHS Foundation Trust tumour and epilepsy neurosurgeons since 2011. METHODS: Patient records of all HH cases operated on since 2011 were reviewed to confirm history of presentation and clinical outcomes. RESULTS: Ten patients have undergone surgery for HH under the dual care of Alder Hey tumour and epilepsy neurosurgeons during this period. Eight cases had a midline transcallosal, interforniceal approach with the remaining 2 having a transcallosal, transforaminal approach. All patients had an IOMRI scan, with 40% needing further tumour resection post-IOMRI. Forty percent had a total resection, 3 patients had near-total resection and 3 patients had subtotal resection (~ 30% tumour residual on post-operative MRI). No new neurological complications developed post-operatively. Hypothalamic axis derangements were seen in 3 cases, including 1 diabetes insipidus with hypocortisolaemia, 1 hypodipsia and 1 transient hyperphagia. Eighty percent are seizure free; the remaining two patients have had significant improvements in seizure frequency. CONCLUSIONS: IOMR was used to tailor the ideal tumour resection volume safely based on anatomy of the lesion, which combined with the open transcallosal, interforniceal route performed by surgeons experienced in the approach resulted in excellent, safe and effective seizure control.

Identifying the biological pathways underlying human focal epilepsy: from complexity to coherence to centrality.

Numerous diverse biological pathways are dysregulated in the epileptic focus. Which of these pathways are most critical in producing the biological abnormalities that lead to epilepsy? Answering this question is key to identifying the primary causes of epilepsy and for discovering new therapeutic strategies with greater efficacy than currently available antiepileptics (AEDs). We have performed the largest genome-wide transcriptomic analysis to date comparing epileptic with normal human hippocampi. We have identified 118 differentially expressed and, for the first time, differentially connected pathways in the epileptic focus. Using network mapping techniques, we have shown that these dysregulated pathways, though seemingly disparate, form a coherent interconnected central network. Using closeness centrality analysis, we have identified that the most influential hub pathways in this network are signalling through G protein-coupled receptors, in particular opioid receptors, and their downstream effectors PKA/CREB and DAG/IP3. Next, we have objectively demonstrated that genetic association of gene sets in independent genome-wide association studies (GWASs) can be used to identify causally relevant gene sets: we show that proven causal epilepsy genes, which cause familial Mendelian epilepsy syndromes, are associated in published sporadic epilepsy GWAS results. Using the same technique, we have shown that central pathways identified (opioid receptor and PKA/CREB and DAG/IP3 signalling pathways) are genetically associated with focal epilepsy and, hence, likely causal. Published functional studies in animal models provide evidence of a role for these pathways in epilepsy. Our work shows that these pathways play a central role in human focal epilepsy and that they are important currently unexploited antiepileptic drug targets.

An integrative in silico system for predicting dysregulated genes in the human epileptic focus: Application to SLC transporters.

OBJECTIVE: Many different gene families are currently being investigated for their potential role in epilepsy and in the response to antiepileptic drugs. A common research challenge is identifying the members of a gene family that are most significantly dysregulated within the human epileptic focus, before taking them forward for resource-intensive functional studies. Published data about transcriptomic changes within the human epileptic focus remains incomplete. A need exists for an accurate in silico system for the prediction of dysregulated genes within the epileptic focus. We present such a bioinformatic system. We demonstrate the validity of our approach by applying it to the solute carrier (SLC) gene family. There are >400 known SLCs. SLCs have never been systematically studied in epilepsy. METHODS: Using our in silico system, we predicted the SLCs likely to be dysregulated in the epileptic focus. We validated our in silico predictions by identifying ex vivo the SLCs dysregulated in epileptic foci, and determining the overlap between our in silico and ex vivo results. For the ex vivo analysis, we used a custom oligonucleotide microarray containing exon probes for all known SLCs to analyze 24 hippocampal samples obtained from surgery for pharmacoresistant mesial temporal lobe epilepsy and 24 hippocampal samples from normal postmortem controls. RESULTS: There was a highly significant (p < 9.99 × 10(-7) ) overlap between the genes identified by our in silico and ex vivo strategies. The SLCs identified were either metal ion exchangers or neurotransmitter transporters, which are likely to play a part in epilepsy by influencing neuronal excitability. SIGNIFICANCE: The identified SLCs are most likely to mediate pharmacoresistance in epilepsy by enhancing the intrinsic severity of epilepsy, but further functional work will be needed to fully evaluate their role. Our successful in silico strategy can be adapted in order to prioritize genes relevant to epilepsy from other gene families.

MRI findings of intracranial anomalies associated with cephalocele--a case series.

INTRODUCTION: Cephalocele is a relatively rare cranial dysraphism characterised by herniation of intracranial structures through the skull. Surgical management is primarily necessary where a risk of infection through communication of the lesion with the intracranial space exists, a risk of rupture, or for cosmetic purposes. Cephalocele is often associated with venous anomalies such as vertical embryonic positioning of the straight sinus, splitting of the superior sagittal sinus, vein of Galen elongation, along with tenting of the tentorium [Morioka et al. Childs Nerv Syst 25:309-315, 2009] PATIENTS: Here, we report four cases of cephalocele with pre-operative MRI imaging retrospectively studied, demonstrating associated venous anomalies. Three of these patients went on to have uncomplicated, corrective surgery, while one was managed conservatively. RESULTS: All four cases demonstrated the main venous drainage going through a persistent falcine sinus to drain into the superior sagittal sinus. Upward tenting of the tentorium was observed in three cases (cases 1, 3 and 4). Two of our cases demonstrated other venous anomalies frequently reported in the literature, namely splitting of the superior sagittal sinus and absence of the transverse sinus (case 1) and communication of the cephalocele with the superior sagittal sinus and absence of the straight sinus (case 2). CONCLUSION: The association between cephalocele and venous anomalies suggests that pre-operative MRI should be mandatory for a full evaluation of a suspicious midline cranial lesion in order to evaluate the safety of corrective surgery.

Positional plagiocephaly: experience with a passive orthotic mattress.

Positional plagiocephaly (deformational or occipital plagiocephaly) is the most common head-shape deformity, which is presented to specialist craniofacial units. The aim of management is to reduce pressure on the affected area in the expectation that brain growth will drive normalization of the head shape. Current management includes a variety of protocols based on repositioning advice or helmet orthotics. The aim of this study is to document changes in head shape associated with use of a passive orthotic mattress for the management of positional plagiocephaly of a series of 30 patients at Alder Hey Children's Hospital between April 2008 and June 2010. Cranial vault asymmetry was assessed before treatment and was classified into mild, moderate, or severe plagiocephaly. Follow-up demonstrated a significant improvement in cranial vault asymmetry in those treated with the passive orthotic mattress.

Extradural abscess secondary to Salmonella enteritidis in a child following fronto-orbital facial advancement and remodeling surgery.

Intracranial infections caused by Salmonella are rare. We describe the first case of a child undergoing craniofacial surgery for trigonocephaly and subsequently developing an extradural abscess secondary to likely community-acquired Salmonella enteritidis. He underwent surgical washout but returned to theater for a further 2, alongside a prolonged course of intravenous ciprofloxacin. We observed extensive anterior skull bone loss at 78 days postoperatively. At 1 year 11 months, extensive anterior skull bone remodeling had taken place, and the child is currently well.

Incidence of cavernoma development in children after radiotherapy for brain tumors.

OBJECT: Cavernous hemangiomas (cavernomas) are benign vascular malformations that may cause seizures and/or hemorrhage when they develop in the brain. The incidence of cavernoma development after brain radiotherapy is unknown. The aim of this study was to assess the prevalence of cavernoma formation in patients who had previously received radiotherapy for brain tumors during childhood. METHODS: All patients were identified who were younger than 16 years of age and had undergone radiotherapy for brain tumors within a 16-year period (January 1, 1988-December 31, 2003). The patient data that were ascertained included age at diagnosis, sex, histopathology results, initial preoperative magnetic resonance (MR) imaging results, date of radiotherapy, and date of detection of cavernoma. Children who were followed up for less than 1 month after radiotherapy or who died during treatment were excluded, as were children with brainstem tumors. All patients had undergone diagnostic MR imaging before receiving radiotherapy, and no vascular malformations were revealed. Of the 379 patients identified, 297 satisfied the inclusion criteria. Ten patients (3.4%) developed cavernomas after radiation therapy. The ages of these patients ranged from 2 to 11 years at the time of radiotherapy (median 7 years), and the latency interval between radiotherapy and cavernoma development was 3 to 102 months (median 37 months). CONCLUSIONS: The prevalence of cavernomas in the present study was more than six times greater than the prevalence rate cited in the literature for this population. The authors conclude that there is an increased risk of developing an intracranial cavernoma after radiotherapy for brain tumors. The possibility of this complication arising should be mentioned when informed consent is sought before treatment using radiotherapy.

Neurosurgical transection of the breast: an unexpected extracranial complication of ventriculoperitoneal shunt insertion.

Ventriculoperitoneal (VP) shunt placement is among the most common surgical procedures undertaken by neurosurgeons. Complications arising from the thoracic portion of the shunt are relatively rare in comparison with those of the intraventricular and peritoneal portions. Disruption of primary breast development following VP shunt placement has not previously been reported. The authors describe the case of a 15-year-old girl referred to the plastic surgery department with a significant right breast deformity and associated asymmetry following VP shunt placement performed during the neonatal period. The calcified shunt was excised and the breast deformity was corrected surgically through multiple scar tissue releases and restoration of the normal breast parenchymal anatomy via a minimally invasive approach, resulting in an excellent aesthetic outcome. This case highlights the potential for injury to occult breast tissue in pediatric patients undergoing VP shunt placement, which can impair subsequent cosmesis and quality of life.

Deep brain stimulation for movement disorders and pain.

Deep brain stimulation (DBS) is an expanding field within neurosurgery. With many neurosurgeons performing relatively small numbers of these procedures, detailed descriptions of the technical aspects and nuances of DBS may be worthwhile. We describe our technique for DBS, based on over 300 procedures. This methodology continues to evolve and is refined according to our own experience, our observations of others, technological innovations, and information derived from the neurosurgical literature. The indications for DBS in our service are outlined, the anatomical targets described, and the anaesthetic and surgical aspects detailed.

Colon atresia and frontal encephalocele: a rare association.

The association of colonic atresia with craniofacial anomalies has been well described and probably represents a malformative event that occurs in the early embryonal period. We present a case of an infant with colonic atresia and a frontal encephalocele and believe this to be a newly reported association. We review possible pathogenic mechanisms.

Do baclofen pumps influence the development of scoliosis in children?

OBJECT: Intrathecal baclofen is an effective treatment for spasticity in patients with cerebral palsy. There has been increasing concern, however, that intrathecal baclofen may accelerate the development of scoliosis in this population. To this end, the authors reviewed their population of pediatric patients with baclofen pumps to assess the incidence of scoliosis. METHODS: This was a retrospective chart and radiology review of all pediatric patients with baclofen pumps. Cobb angles were measured preoperatively and on follow-up images. RESULTS: Of 38 patients identified, 32 had adequate data available for inclusion in the study (16 with cerebral palsy, 7 with dystonic cerebral palsy, 4 with head injury, and 5 with other diagnoses). The mean age at pump insertion was 10.6 years and the mean follow-up period was 31 months (range 1-118 months). The mean annual Cobb angle progression was 19 degrees (range 0-68 degrees, median 12 degrees). CONCLUSIONS: In the authors' group of patients there was notable development and progression of scoliosis at a greater than previously reported rate for the same patient population, and also greater than previously reported patients with intrathecal baclofen pumps. The largest possible confounding factor in this study was the insertion of the pump before skeletal maturity and therefore coinciding with the time when scoliosis may be developing naturally. A prospective study is recommended to gather further data on the development of scoliosis in this particular population with intrathecal baclofen pumps.

Management of osteoblastoma and osteoid osteoma of the spine in childhood.

OBJECT: Osteoid osteomas and osteoblastoma of the spine are rare lesions in childhood, and management strategies have changed. The authors reviewed their recent experience with these 2 types of lesions to elucidate current treatment modalities and outcomes. METHODS: Case records and radiographic images from all cases of osteoid osteoma and osteoblastoma diagnosed between 1993 and 2008 were retrospectively reviewed, including those managed nonsurgically. RESULTS: Thirty cases were identified; 22 were treated surgically and 8 were managed nonsurgically. The patients' mean age at presentation was 13 years (range 3-17 years). Of 30 patients, 29 (97%) presented with pain; 7 (23%) had scoliosis at presentation; 12 (40%) experienced relief with nonsteroidal antiinflammatory medication. Osteoid osteoma was diagnosed in 7 (32%) of the 22 patients who underwent surgery, and osteoblastoma in 15 (68%). Nine (41%) of the 22 surgically treated patients underwent fusion procedures (bone onlay or instrumentation) at the time of surgery. Pain freedom without medication had been achieved in 16 (73%) of the 22 surgically treated patients at a mean follow-up of 28 months (range 2-75 months) and was confirmed in 3 (38%) of the 8 nonsurgically treated patients at a mean follow-up of 33 months (range 24-51 months). CONCLUSIONS: Osteoid osteomas and osteoblastomas can present challenging management problems in pediatric patients. In the majority of cases in which conservative therapy fails or pathological diagnosis is required, surgery using modern intraoperative imaging and spinal instrumentation can provide symptom relief and tumor control.