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Deletions at 16p13.11 are associated with schizophrenia, mental retardation, and most recently idiopathic generalized epilepsy. To evaluate the role of 16p13.11 deletions, as well as other structural variation, in epilepsy disorders, we used genome-wide screens to identify copy number variation in 3812 patients with a diverse spectrum of epilepsy syndromes and in 1299 neurologically-normal controls. Large deletions (> 100 kb) at 16p13.11 were observed in 23 patients, whereas no control had a deletion greater than 16 kb. Patients, even those with identically sized 16p13.11 deletions, presented with highly variable epilepsy phenotypes. For a subset of patients with a 16p13.11 deletion, we show a consistent reduction of expression for included genes, suggesting that haploinsufficiency might contribute to pathogenicity. We also investigated another possible mechanism of pathogenicity by using hybridization-based capture and next-generation sequencing of the homologous chromosome for ten 16p13.11-deletion patients to look for unmasked recessive mutations. Follow-up genotyping of suggestive polymorphisms failed to identify any convincing recessive-acting mutations in the homologous interval corresponding to the deletion. The observation that two of the 16p13.11 deletions were larger than 2 Mb in size led us to screen for other large deletions. We found 12 additional genomic regions harboring deletions > 2 Mb in epilepsy patients, and none in controls. Additional evaluation is needed to characterize the role of these exceedingly large, non-locus-specific deletions in epilepsy. Collectively, these data implicate 16p13.11 and possibly other large deletions as risk factors for a wide range of epilepsy disorders, and they appear to point toward haploinsufficiency as a contributor to the pathogenicity of deletions.

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Partial epilepsies have a substantial heritability. However, the actual genetic causes are largely unknown. In contrast to many other common diseases for which genetic association-studies have successfully revealed common variants associated with disease risk, the role of common variation in partial epilepsies has not yet been explored in a well-powered study. We undertook a genome-wide association-study to identify common variants which influence risk for epilepsy shared amongst partial epilepsy syndromes, in 3445 patients and 6935 controls of European ancestry. We did not identify any genome-wide significant association. A few single nucleotide polymorphisms may warrant further investigation. We exclude common genetic variants with effect sizes above a modest 1.3 odds ratio for a single variant as contributors to genetic susceptibility shared across the partial epilepsies. We show that, at best, common genetic variation can only have a modest role in predisposition to the partial epilepsies when considered across syndromes in Europeans. The genetic architecture of the partial epilepsies is likely to be very complex, reflecting genotypic and phenotypic heterogeneity. Larger meta-analyses are required to identify variants of smaller effect sizes (odds ratio <1.3) or syndrome-specific variants. Further, our results suggest research efforts should also be directed towards identifying the multiple rare variants likely to account for at least part of the heritability of the partial epilepsies. Data emerging from genome-wide association-studies will be valuable during the next serious challenge of interpreting all the genetic variation emerging from whole-genome sequencing studies.

Generalized periodic epileptiform discharges (GPEDs) are generalized, synchronous electrographic discharges. This study investigates etiologies, relationship to status epilepticus (SE), and the prognosis for patients with GPEDs. All EEGs with GPEDs performed at Duke University Medical Center between January 1994 and October 1995 were identified. Clinical histories and EEGs were reviewed. They were divided into groups depending on the etiology of the GPEDs, whether the patients were in SE or not, and whether they were alive or not at discharge. A comparison of histories and GPED characteristics among groups was undertaken using parametric and nonparametric t tests. Twenty-five patients were enrolled: 7 (28%) had toxic-metabolic encephalopathy, 10 (40%) had anoxia and toxic-metabolic encephalopathy, and 8 (32%) had a primary neurologic process. Eight patients (32%) were in SE. In the SE group, GPED amplitude was higher (110 versus 80 microV, P < 0.05), GPED duration was longer (0.5 versus 0.3 seconds, P < 0.05), and inter-GPED amplitude was higher (34 versus 17 microV, P < 0.05). Nine patients (36%) were alive at discharge; they were more likely to be younger (51 versus 68 years, P < 0.05), have a better mental status at the time of their EEG, and have a higher inter-GPED amplitude (33 versus 18 microV, P < 0.05). A variety of conditions, including SE, can cause GPEDs. Intergroup differences in historic and GPED features exist between those patients in SE and those not in SE and those with good and poor prognoses.

and xUCB Pharma, Raleigh, North Carolina, U.S.A. SUMMARYPurpose: To evaluate the long-term (up to 5 years exposure) safety and efficacy of lacosamide as adjunctive therapy in patients with uncontrolled partial-onset seizures taking one to three concomitant antiepileptic drugs (AEDs) in open-label extension trial SP756 (NCT00522275). Methods: Patients who completed the double-blind trial SP754 (NCT00136019) were eligible to participate in this open-label extension trial (SP756). At the conclusion of trial SP754, patients had transitioned to lacosamide 200 mg/day. Subsequent dosage adjustments of lacosamide (100-800 mg/day) and/or concomitant AEDs were allowed to optimize tolerability and seizure reduction. Treatment-emergent adverse events (TEAEs), vital signs, body weight, clinical laboratory data, electrocardiography studies, and seizure frequency were evaluated. Key Findings: A total of 308 patients received open-label lacosamide and 138 patients (44.8%) completed the longterm trial. The median modal dose (defined as the daily lacosamide dose a patient received for the longest duration during the treatment period) was 500 mg/day. The percentages of patients with lacosamide exposure >1, >2, >3, or >4 years were 75%, 63%, 54%, and 29%, respectively. Primary reasons for discontinuation were lack of efficacy (26%) and adverse events (11%). Common TEAEs ( ‡15%) were dizziness, headache, contusion, nausea, convulsion, nasopharyngitis, fall, vomiting, and diplopia. TEAEs that led to discontinuation in ‡1.0% of patients were dizziness (1.6%) and convulsion (1.0%). The median percent reductions from baseline of trial SP754 in 28-day seizure frequency were 53.4%, 55.2%, 58.1%, and 62.5%, respectively, for 1-, 2-, 3-, and 4-year completers. The ‡50% responder rates were 52.8%, 56.5%, 58.7%, and 62.5% for 1-, 2-, 3-, and 4-year completers, respectively. Seven of eight patients on lacosamide monotherapy for ‡12 months were deemed 50% responders. Of patients exposed to lacosamide ‡2 years, 3.1% remained seizure-free for a period ‡2 years. Significance: Long-term (up to 5 years) lacosamide treatment was generally well tolerated. The safety profile of lacosamide observed in this trial is consistent with that established in previous double-blind, placebo-controlled trials. Although the open-label trial design limits the analysis of efficacy, long-term reduction in seizure frequency and maintenance of efficacy was observed.

Background: Non-convulsive status epilepticus (NCSE) is status epilepticus without obvious tonic-clonic activity. Patients with NCSE have altered mental state. An EEG is needed to confirm the diagnosis, but obtaining an EEG on every patient with altered mental state is not practical. Objective: To determine whether clinical features could be used to predict which patients were more likely to be in NCSE and thus in need of an urgent EEG. Methods: Over a six month period, all patients for whom an urgent EEG was ordered to identify NCSE were enrolled. Neurology residents examined the patients and filled out a questionnaire without knowledge of the EEG results. The patients were divided into two groups, NCSE and non-NCSE, depending on the EEG result. The clinical features were compared between the two groups. The sensitivity and specificity of the features were calculated. Results: 48 patients were enrolled, 12 in NCSE and 36 not in NCSE. Remote risk factors for seizures, severely impaired mental state, and ocular movement abnormalities were seen significantly more often in the NCSE group. The combined sensitivity of remote risk factors for seizures and ocular movement abnormalities was 100%. Conclusions: There are certain clinical features that are more likely to be present in patients in NCSE compared with other types of encephalopathy. Either remote risk factors for seizures or ocular movement abnormalities were seen in all patients in NCSE. These features may be used to select which patients should have an urgent EEG.