Developing a gene panel for pharmacoresistant epilepsy: a review of epilepsy pharmacogenetics

Ketogenic diet therapies as a non-pharmacological adjuvant in resistant epilepsy: retrospective analysis of adult outpatients in Colombia

Twelve patients between 18 and 53 years of age were included. MAD plus nutritional supplementation was administered to 75% (n = 10) of the participants, one (8.3%) received MAD alone, and 16.7 (n = 2) received Classic Ketogenic Diet (cKD) plus nutritional supplementation. Oral nutritional supplementation, administered in the outpatient setting, provided patients with between 31 and 55% of the total caloric value. In the first month of KDT treatment, 83.3% (n = 10) of patients reduced the number of weekly seizures by 40% (median). At six months of treatment, 75% of patients had at least halved the number of weekly seizures. At 12 months of treatment, the number of weekly seizures had been reduced by 85.7% (median). KDT was well tolerated, and there was no need to discontinue treatment. This study provides real-world information on the use of KDT, particularly MAD in adults, in developing countries. Future studies in larger cohorts will provide further information on different types of KDT, adherence, and patient-reported outcomes.

Should secondary pharmacogenomic variants be actively screened and reported when diagnostic genome-wide sequencing is performed in a child?

This white paper was prepared by the Global Alliance for Genomics and Health Regulatory and Ethics Work Stream's Pediatric Task Team to review and provide perspective with respect to ethical, legal, and social issues regarding the return of secondary pharmacogenomic variants in children who have a serious disease or developmental disorder and are undergoing exome or genome sequencing to identify a genetic cause of their condition. We discuss actively searching for and reporting pharmacogenetic/genomic variants in pediatric patients, different methods of returning secondary pharmacogenomic findings to the patient/parents and/or treating clinicians, maintaining these data in the patient's health record over time, decision supports to assist using pharmacogenetic results in future treatment decisions, and sharing information in public databases to improve the clinical interpretation of pharmacogenetic variants identified in other children. We conclude by presenting a series of points to consider for clinicians and policymakers regarding whether, and under what circumstances, routine screening and return of pharmacogenomic variants unrelated to the indications for testing is appropriate in children who are undergoing genome-wide sequencing to assist in the diagnosis of a suspected genetic disease.

Current Considerations in the Diagnosis and Treatment of Circadian Rhythm Sleep-Wake Disorders in Children

Circadian Rhythm Sleep-Wake Disorders (CRSWDs) are important sleep disorders whose unifying feature is a mismatch between the preferred or required times for sleep and wakefulness and the endogenous circadian drives for these. Their etiology, presentation, and treatment can be different in pediatric patients as compared to adults. Evaluation of these disorders must be performed while viewed through the lens of a patient's comorbid conditions. Newer methods of assessment promise to provide greater diagnostic clarity and critical insights into how circadian physiology affects overall health and disease states. Effective clinical management of CRSWDs is multimodal, requiring an integrated approach across disciplines. Therapeutic success depends upon appropriately timed nonpharmacologic and pharmacologic interventions. A better understanding of the genetic predispositions for and causes of CRSWDs has led to novel clinical opportunities for diagnosis and improved therapeutics.

Experiences of adults living with refractory epilepsy and their views and expectations on receiving results from whole genome sequencing

INTRODUCTION

Researchers, clinicians and patients are turning to new innovations in research and clinical practice to further their knowledge in the genetic domain and improve diagnostics or treatment. However, with increased knowledge in genetics, societal issues may arise. Being conscious of these issues is crucial in order to implement standardized and efficient testing on a wider scale that is accessible to a greater number of individuals while simultaneously returning test results, including incidental findings, in a timely manner.

METHODS

Within the framework of a genomics research project, we invited 20 participants who suffer from refractory epilepsy to provide insight on their personal experiences with epilepsy, as well as their thoughts on receiving Whole Genome Sequencing (WGS) results and with whom they would feel comfortable sharing these results with.

RESULTS

All participants had their own unique experience with epilepsy, such as how they handled their diagnosis, their struggles following the diagnosis, the healthcare services they received, how they shared their diagnosis with others, and how they managed stigmatization from others. Most participants would be eager to know their WGS results, whether the results be related to epilepsy (n = 19), response to pharmaceutical drugs including AEDs (n = 16), comorbidities (n = 19) and incidental findings (n = 15).

CONCLUSION

Our findings reinforce the need to improve access to genetic testing for epilepsy patients in clinical settings. Furthermore, while acquiring more genetic knowledge (i.e. WGS) about epilepsy can provide answers for the affected population, it also requires the simultaneous involvement of several medical disciplines, with greater emphasis on genetic and psychological counseling.

GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment.

A real-life pilot study of the clinical application of pharmacogenomics testing on saliva in epilepsy

Response to antiseizure medications (ASMs) can be influenced by several gene polymorphisms, causing either lower efficacy or higher occurrence of adverse drug reactions (ADRs). We investigated the clinical utility of salivary pharmacogenomic testing on epilepsy patients. A commercialized pharmacogenomic salivary test was performed in a cohort of epileptic patients. Genetic variants on five genes (i.e., CYP1A2, CYP2C9, CYP2C19, EPHX1, and ABCB1) involved in common ASMs metabolism were selected. Twenty-one individuals (median age [Q1 -Q3 ]: 15 [6.5-28] years) were enrolled. Six patients harboring the homozygous *1F allele in CYP1A2 could have reduced chance of response to stiripentol due to fast metabolism. CYP2C9 had reduced activity in 10 patients (alleles *2 and *3), potentially affecting phenytoin (PHT), phenobarbital (PB), primidone, lacosamide (LCM), and valproic acid metabolism. Seven patients, carrying the *2 allele of CYP2C19, had an increased risk of ADRs with clobazam (CLB), PB, PHT, LCM, brivaracetam; while one individual with the *17 allele in heterozygosity reported a CLB fast metabolism. Six patients showed a CC polymorphism of EPHX1 associated with the impaired efficacy of carbamazepine. ABCB1 polymorphisms related to drug-resistance (3435 CC) or drug-sensitive phenotype (CT or TT) were found in 6 out of 7 patients. Pharmacogenomic testing on saliva proved easy and safe in clinical practice to convey information for the management of epileptic patients, especially those resistant to treatment or sensitive to severe ADRs.

Systemic inflammation as a biomarker of seizure propensity and a target for treatment to reduce seizure propensity

People with diabetes can wear a device that measures blood glucose and delivers just the amount of insulin needed to return the glucose level to within bounds. Currently, people with epilepsy do not have access to an equivalent wearable device that measures a systemic indicator of an impending seizure and delivers a rapidly acting medication or other intervention (e.g., an electrical stimulus) to terminate or prevent a seizure. Given that seizure susceptibility is reliably increased in systemic inflammatory states, we propose a novel closed-loop device where release of a fast-acting therapy is governed by sensors that quantify the magnitude of systemic inflammation. Here, we review the evidence that patients with epilepsy have raised levels of systemic indicators of inflammation than controls, and that some anti-inflammatory drugs have reduced seizure occurrence in animals and humans. We then consider the options of what might be incorporated into a responsive anti-seizure system.

Gene panel to guide antiseizure medication prescribing: Does the cost justify the benefits?

Pharmacogenomics hold the potential to identify variants associated with adverse drug reactions and treatment efficacy of anti-seizure medications. A model-based cost-utility analysis by Gordon and colleagues showed that genetically-guided therapy costs more, yielded higher quality-adjusted life years outcomes, and was considered to be cost-effective compared to usual care. The study provided preliminary evidence on the value of pharmacogenetic testing in patients with drug-resistant epilepsy. However, data input for the model was based on assumptions that need to be empirically tested. Further, there are many other factors that may affect the cost-effectiveness of pharmacogenetic testing that need to be considered, including the model of service delivery, its implementation in complex clinical service, whether clinicians will modify treatment decisions based on pharmacogenetic information, and the fidelity with which recommendation on testing is adhered to in the real-world. The cost-effectiveness analysis should be repeated when more robust data on the effectiveness of pharmacogenetics are available and conducted alongside a budget impact analysis, incorporating the direct health care resources required to implement widespread testing and potential subsequent changes in treatment.

Dysfunction of ABC Transporters at the Surface of BBB: Potential Implications in Intractable Epilepsy and Applications of Nanotechnology Enabled Drug Delivery

Epilepsy is a chronic neurological disorder affecting 70 million people globally. One of the fascinating attributes of brain microvasculature is the (BBB), which controls a chain of distinct features that securely regulate the molecules, ions, and cells movement between the blood and the parenchyma. The barrier's integrity is of paramount importance and essential for maintaining brain homeostasis, as it offers both physical and chemical barriers to counter pathogens and xenobiotics. Dysfunction of various transporters in the (BBB), mainly ATP binding cassette (ABC), is considered to play a vital role in hampering the availability of antiepileptic drugs into the brain. ABC (ATP-binding cassette) transporters constitute a most diverse protein superfamily, which plays an essential part in various biological processes, including cell homeostasis, cell signaling, uptake of nutrients, and drug metabolism. Moreover, it plays a crucial role in neuroprotection by out-flowing various internal and external toxic substances from the interior of a cell, thus decreasing their buildup inside the cell. In humans, forty-eight ABC transporters have been acknowledged and categorized into subfamilies A to G based on their phylogenetic analysis. ABC subfamilies B, C, and G, impart a vital role at the BBB in guarding the brain against the entrance of various xenobiotic and their buildup. The illnesses of the central nervous system have received a lot of attention lately Owing to the existence of the BBB, the penetration effectiveness of most CNS medicines into the brain parenchyma is very limited (BBB). In the development of neurological therapies, BBB crossing for medication delivery to the CNS continues to be a major barrier. Nanomaterials with BBB cross ability have indeed been extensively developed for the treatment of CNS diseases due to their advantageous properties. This review will focus on multiple possible factors like inflammation, oxidative stress, uncontrolled recurrent seizures, and genetic polymorphisms that result in the deregulation of ABC transporters in epilepsy and nanotechnology-enabled delivery across BBB in epilepsy.

Simultaneous Determination of Lamotrigine, Oxcarbazepine, Lacosamide, and Topiramate in Rat Plasma by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

This study established an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to study the pharmacokinetics of four antiepileptic drugs, lamotrigine, oxcarbazepine, lacosamide, and topiramate, in rats after oral administration. The gradient elution was performed on a UPLC HSS T3 (2.1 mm × 100 mm, 1.8 μm) column with acetonitrile-0.1% formic acid as the mobile phase at a flow rate of 0.4 mL/min. Protein precipitation by acetonitrile was adopted for plasma sample pretreatment. Electrospray- (ESI-) positive/negative ion switching and multiple reaction monitoring (MRM) modes were adopted for ion quantitative determination of antiepileptic drugs. UPLC-MS/MS detection and Drug and Statistics (DAS) software fitting were performed to blood samples collected from rats after oral administration of lamotrigine, oxcarbazepine, lacosamide, and topiramate (5 mg/kg). All drugs examined showed linearity within 5–5000 ng/ml (R2 > 0.9987), the intraday accuracy was within 92%–108%, and the interday accuracy was within 93%–109%. The relative standard deviations (RSD) of intraday and interday were less than 15%. The matrix effect was within 91%–105%, and the recovery was better than 88%. The established UPLC-MS/MS method was successfully applied to the pharmacokinetic study of lamotrigine, oxcarbazepine, lacosamide, and topiramate in rats.

Novel treatments in epilepsy guided by genetic diagnosis

In recent years, precision medicine has emerged as a new paradigm for improved and more individualized patient care. Its key objective is to provide the right treatment, to the right patient at the right time, by basing medical decisions on individual characteristics, including specific genetic biomarkers. In order to realize this objective researchers and physicians must first identify the underlying genetic cause; over the last 10 years, advances in genetics have made this possible for several monogenic epilepsies. Through next generation techniques, a precise genetic aetiology is attainable in 30-50% of genetic epilepsies beginning in the paediatric age. While committed in such search for novel genes carrying disease-causing variants, progress in the study of experimental models of epilepsy has also provided a better understanding of the mechanisms underlying the condition. Such advances are already being translated into improving care, management and treatment of some patients. Identification of a precise genetic aetiology can already direct physicians to prescribe treatments correcting specific metabolic defects, avoid antiseizure medicines that might aggravate functional consequences of the disease-causing variant or select the drugs that counteract the underlying, genetically determined, functional disturbance. Personalized, tailored treatments should not just focus on how to stop seizures but possibly prevent their onset and cure the disorder, often consisting of seizures and its comorbidities including cognitive, motor and behaviour deficiencies. This review discusses the therapeutic implications following a specific genetic diagnosis and the correlation between genetic findings, pathophysiological mechanisms and tailored seizure treatment, emphasizing the impact on current clinical practice.

Queensland Genomics: an adaptive approach for integrating genomics into a public healthcare system

The establishment of genomics in health care systems has been occurring for the past decade. It is recognised that implementing genomics within a health service is challenging without a system-wide approach. Globally, as clinical genomics implementation programs have matured there is a growing body of information around program design and outcomes. Program structures vary depending on local ecosystems including the health system, politics and funding availability, however, lessons from other programs are important to the design of programs in different jurisdictions. Here we describe an adaptive approach to the implementation of genomics into a publicly funded health care system servicing a population of 5.1 million people. The adaptive approach enabled flexibility to facilitate substantial changes during the program in response to learnings and external factors. We report the benefits and challenges experienced by the program, particularly in relation to the engagement of people and services, and the design of both individual projects and the program as a whole.