Faculty Bibliography

Purpose: Evaluate the dose-ranging safety, tolerability, and pharmacokinetics (PK) of CBD in children with Dravet syndrome (DS). Method: Patients aged 4-10 years completed a 4-week baseline period and were randomised 4:1 to 1 of 3 CBD doses (5, 10, 20 mg/kg/day) or placebo as add-on therapy for 3 weeks. CBD (25 or 100 mg/mL oral solution) was administered BID starting at 2.5 mg/kg/day and increasing by 2.5 mg/kg QOD to randomised dose. On Days 1 and 22, PK exposures were expressed as AUC0-t. Dose proportionality was assessed on Day 22 by regression analysis. Adverse events (AEs) were recorded daily. Results: 34 patients were randomised to CBD 5 mg/kg/day (n = 10), 10 mg/kg/day (n = 8), 20 mg/kg/day (n = 9), or placebo (n = 7). Patients took a median 3 antiepileptic drugs (AEDs). On Day 22, exposures to CBD and major metabolites increased dose-proportionally; there was minimal change in clobazam levels, but concentrations of clobazam's metabolite, N-clobazam, increased independent of CBD dose, except in patients on stiripentol. There was no demonstrable effect on other AEDs (valproic acid, topiramate, stiripentol, levetiracetam). Most common AEs (CBD vs. placebo) were pyrexia (22% vs. 0%), somnolence (19% vs. 14%), decreased appetite (19% vs. 0%), and sedation (15% vs. 0%). Treatment-related serious AEs occurred in 2 patients on CBD and discontinuations due to AEs occurred in 2 patients on CBD. Increases in ALT or AST (levels >3 9 ULN) occurred in 6 patients on CBD, all on valproic acid; none had elevated bilirubin and all recovered. Conclusion: CBD was well tolerated and 20 mg/kg/day was chosen for further development. Exposure to CBD and its metabolites increased dose-proportionally. A PK interaction of CBD on N-clobazam was observed, likely mediated through CYP2C19 inhibition, except with stiripentol, presumably from prior saturated inhibition of CYP2C19 by stiripentol

BACKGROUND:Genetic variant interpretation contributes to testing yield differences reported for sudden unexplained death. Adapting a high-resolution variant interpretation framework, which considers disease prevalence, reduced penetrance, genetic heterogeneity, and allelic contribution to determine the maximum tolerated allele count in gnomAD, we report an evaluation of cardiac channelopathy and cardiomyopathy genes in a large, demographically diverse sudden unexplained death cohort that underwent thorough investigation in the United States' largest medical examiner's office. METHODS AND RESULTS/RESULTS:The cohort has 296 decedents: 147 Blacks, 64 Hispanics, 49 Whites, 22 Asians, and 14 mixed ethnicities; 142 infants (1 to 11 months), 39 children (1 to 17 years), 74 young adults (18 to 34 years), and 41 adults (35 to 55 years). Eighty-nine cardiac disease genes were evaluated. Using a high-resolution variant interpretation workflow, we classified 17 variants as pathogenic or likely pathogenic (2 of which were incidental findings and excluded in testing yield analysis), 46 novel variants of uncertain significance, and 130 variants of uncertain significance. Nine pathogenic or likely pathogenic variants in ClinVar were reclassified to likely benign and excluded in testing yield analysis. The yields of positive cases by ethnicity and age were 21.4% in mixed ethnicities, 10.2% Whites, 4.5% Asians, 3.1% Hispanics, and 2% Blacks; 7.7% children, 7.3% in adults, 5.4% young adults, and 2.8% infants. The percentages of uncertain cases with variants of uncertain significance by ethnicity were 45.5% in Asians, 45.3% Hispanics, 44.20% Blacks, 36.7% Whites, and 14.3% in mixed ethnicities. CONCLUSIONS:High-resolution variant interpretation provides diagnostic accuracy and healthcare efficiency. Under-represented populations warrant greater inclusion in future studies.

Animal studies support the hypothesis that in slow-wave sleep, replay of waking neocortical activity under hippocampal guidance leads to memory consolidation. However, no intracranial electrophysiological evidence for replay exists in humans. We identified consistent sequences of population firing peaks across widespread cortical regions during complete waking periods. The occurrence of these "Motifs" were compared between sleeps preceding the waking period ("Sleep-Pre") when the Motifs were identified, and those following ("Sleep-Post"). In all subjects, the majority of waking Motifs (most of which were novel) had more matches in Sleep-Post than in Sleep-Pre. In rodents, hippocampal replay occurs during local sharp-wave ripples, and the associated neocortical replay tends to occur during local sleep spindles and down-to-up transitions. These waves may facilitate consolidation by sequencing cell-firing and encouraging plasticity. Similarly, we found that Motifs were coupled to neocortical spindles, down-to-up transitions, theta bursts, and hippocampal sharp-wave ripples. While Motifs occurring during cognitive task performance were more likely to have more matches in subsequent sleep, our studies provide no direct demonstration that the replay of Motifs contributes to consolidation. Nonetheless, these results confirm a core prediction of the dominant neurobiological theory of human memory consolidation.

Transcranial electrical stimulation has widespread clinical and research applications, yet its effect on ongoing neural activity in humans is not well established. Previous reports argue that transcranial alternating current stimulation (tACS) can entrain and enhance neural rhythms related to memory, but the evidence from non-invasive recordings has remained inconclusive. Here, we measure endogenous spindle and theta activity intracranially in humans during low-frequency tACS and find no stable entrainment of spindle power during non-REM sleep, nor of theta power during resting wakefulness. As positive controls, we find robust entrainment of spindle activity to endogenous slow-wave activity in 66% of electrodes as well as entrainment to rhythmic noise-burst acoustic stimulation in 14% of electrodes. We conclude that low-frequency tACS at common stimulation intensities neither acutely modulates spindle activity during sleep nor theta activity during waking rest, likely because of the attenuated electrical fields reaching the cortical surface.

Gene identification in epilepsy has mainly been limited to large families segregating genes of major effect and de novo mutations in epileptic encephalopathies. Many families that present with common non-acquired focal epilepsies and genetic generalized epilepsies remain unexplained. We assembled a cohort of 'genetically enriched' common epilepsies by collecting and phenotyping families containing multiple individuals with unprovoked seizures. We aimed to determine if specific clinical epilepsy features aggregate within families, and whether this segregation of phenotypes may constitute distinct 'familial syndromes' that could inform genomic analyses. Families with three or more individuals with unprovoked seizures were studied across multiple international centres. Affected individuals were phenotyped and classified according to specific electroclinical syndromes. Families were categorized based on syndromic groupings of affected family members, examined for pedigree structure and phenotypic patterns and, where possible, assigned specific familial epilepsy syndromes. A total of 303 families were assembled and analysed, comprising 1120 affected phenotyped individuals. Of the 303 families, 117 exclusively segregated generalized epilepsy, 62 focal epilepsy, and 22 were classified as genetic epilepsy with febrile seizures plus. Over one-third (102 families) were observed to have mixed epilepsy phenotypes: 78 had both generalized and focal epilepsy features within the same individual (n = 39), or within first or second degree relatives (n = 39). Among the genetic generalized epilepsy families, absence epilepsies were found to cluster within families independently of juvenile myoclonic epilepsy, and significantly more females were affected than males. Of the 62 familial focal epilepsy families, two previously undescribed familial focal syndrome patterns were evident: 15 families had posterior quadrant epilepsies, including seven with occipito-temporal localization and seven with temporo-parietal foci, and four families displayed familial focal epilepsy of childhood with multiple affected siblings that was suggestive of recessive inheritance. The findings suggest (i) specific patterns of syndromic familial aggregation occur, including newly recognized forms of familial focal epilepsy; (ii) although syndrome-specificity usually occurs in multiplex families, the one-third of families with features of both focal and generalized epilepsy is suggestive of shared genetic determinants; and (iii) patterns of features observed across families including pedigree structure, sex, and age of onset may hold clues for future gene identification. Such detailed phenotypic information will be invaluable in the conditioning and interpretation of forthcoming sequencing data to understand the genetic architecture and interrelationships of the common epilepsy syndromes.

Objective: Assess the effect of adjunctive CBD for treatment of drug-resistant seizures in Dravet syndrome. Methods: This double-blind, placebo-controlled trial randomized 120 children aged 2-18 years with Dravet syndrome and drug-resistant seizures to receive CBD oral solution 20 mg/kg/ day (n=61) or placebo (n=59) for 14 weeks (2 week titration; 12 week maintenance). The primary endpoint was the percentage change from baseline in convulsive seizures (tonic-clonic, tonic, clonic, and atonic) frequency over the 14-week treatment period. Results: The groups were well-balanced at baseline for demographics. Mean age was 10 years, with 29% of patients <6 years. Patients had previously tried a median 4 AEDs, and were currently taking a median 3 AEDs. Convulsive seizure frequency per month decreased from a median of 12.4 to 5.9 (median reduction of 39%) with CBD versus 14.9 to 14.1 (median reduction of 13%) with placebo (difference between groups of 23%; p=0.012). The proportion of patients with e50% reduction in convulsive seizure frequency was 42.6% with CBD versus 27.1% with placebo (OR=2.0; p=0.078). Adverse events (AEs) occurred in 93.4% of CBD and 74.6% of placebo patients, and were mostly mild or moderate; the most common were somnolence, diarrhea, and decreased appetite. Serious AEs were reported in 16.4% of CBD and 5.1% of placebo patients, and were considered treatment-related in 8.2% of CBD patients, all of whom discontinued CBD. Some elevations in transaminases were noted without elevations of bilirubin; all were on concomitant valproate and all resolved. There were no deaths in the study. Conclusions: In this study, CBD resulted in a significantly greater reduction in convulsive seizure frequency than placebo; adverse events were more frequent with CBD, but it was generally well tolerated

OBJECTIVE: To determine the definite and potential frequency of seizures and epilepsy as a cause of death (COD) and how often this goes unrecognized. METHODS: Prospective determination of seizures or epilepsy and final COD for individuals aged 18-90 years with out-of-hospital sudden cardiac deaths (SCDs) from the population-based San Francisco POST SCD Study. We compared prospective seizure or epilepsy diagnosis and final COD as adjudicated by a multidisciplinary committee (pathologists, electrophysiologists, and a vascular neurologist) vs retrospective adjudication by 2 epileptologists with expertise in seizure-related mortality. RESULTS: Of 541 SCDs identified during the 37-month study period (mean age 62.8 years, 69% men), 525 (97%) were autopsied; 39/525 (7.4%) had seizures or epilepsy (mean age: 58 years, range: 27-92; 67% men), comprising 17% of 231 nonarrhythmic sudden deaths. The multidisciplinary team identified 15 cases of epilepsy, 6 sudden unexpected deaths in epilepsy (SUDEPs), and no deaths related to acute symptomatic seizures. The epileptologists identified 25 cases of epilepsy and 8 definite SUDEPs, 10 possible SUDEPs, and 5 potential cases of acute symptomatic seizures as a COD. CONCLUSIONS: Among the 25 patients identified with epilepsy by the epileptologists, they found definite or possible SUDEP in 72% (18/25) vs 24% (6/25) by the multidisciplinary group (6/15 cases they identified with epilepsy). The epileptologists identified acute symptomatic seizures as a potential COD in 5/14 patients with alcohol-related seizures. Epilepsy is underdiagnosed among decedents. Among patients with seizures and epilepsy who die suddenly, seizures and SUDEP often go unrecognized as a potential or definite COD.