Beth Rosen Sheidley

Extending the KCNQ2 encephalopathy spectrum Clinical and neuroimaging findings in 17 patients

Objectives: To determine the frequency of KCNQ2 mutations in patients with neonatal epileptic encephalopathy (NEE), and to expand the phenotypic spectrum of KCNQ2 epileptic encephalopathy. Methods: Eighty-four patients with unexplained NEE were screened for KCNQ2 mutations using classic Sanger sequencing. Clinical data of 6 additional patients with KCNQ2 mutations detected by gene panel were collected. Detailed phenotyping was performed with particular attention to seizure frequency, cognitive outcome, and video-EEG. Results: In the cohort, we identified 9 different heterozygous de novo KCNQ2 missense mutations in 11 of 84 patients (13%). Two of 6 missense mutations detected by gene panel were recurrent and present in patients of the cohort. Seizures at onset typically consisted of tonic posturing often associated with focal clonic jerking, and were accompanied by apnea with desaturation. One patient diagnosed by gene panel had seizure onset at the age of 5 months. Based on seizure frequency at onset and cognitive outcome, we delineated 3 clinical subgroups, expanding the spectrum of KCNQ2 encephalopathy to patients with moderate intellectual disability and/or infrequent seizures at onset. Recurrent mutations lead to relatively homogenous phenotypes. One patient responded favorably to retigabine; 5 patients had a good response to carbamazepine. In 6 patients, seizures with bradycardia were recorded. One patient died of probable sudden unexpected death in epilepsy. Conclusion: KCNQ2 mutations cause approximately 13% of unexplained NEE. Patients present with a wide spectrum of severity and, although rare, infantile epilepsy onset is possible.

Copy number variation plays an important role in clinical epilepsy

To evaluate the role of copy number abnormalities detectable using chromosomal microarray (CMA) testing in patients with epilepsy at a tertiary care center.

Genetic testing in the epilepsies-developments and dilemmas.

In the past two decades, the number of genes recognized to have a role in the epilepsies has dramatically increased. The availability of testing for epilepsy-related genes is potentially helpful for clarification of the diagnosis and prognosis, selection of optimal treatments, and provision of information for family planning. For some patients, identification of a specific genetic cause of their epilepsy has important personal value, even in the absence of clear clinical utility. The availability of genetic testing also raises new issues that have only begun to be considered. These issues include the growing importance of educating physicians about when and how to test patients, the need to ensure that affected individuals and their families can make informed choices about testing and receive support after receiving the results, and the question of what the positive and negative consequences of genetic testing will be for affected individuals, their family members, and society.

Genetics and genotype–phenotype correlations in early onset epileptic encephalopathy with burst suppression

We sought to identify genetic causes of early onset epileptic encephalopathies with burst suppression (Ohtahara syndrome and early myoclonic encephalopathy) and evaluate genotype–phenotype correlations.

Genetics in clinical epilepsy: Issues in genetic testing and counseling

In the last decade, major advances have been made in our understanding of the genetic basis of epilepsy. Genetic testing for over two dozen epilepsy-related genes is now clinically available, and healthcare providers who manage patients with epilepsy are faced with incorporating genetic information into their assessment and treatment plans. Although the clinical applications of genetic test results in the setting of epilepsy may be somewhat limited, an argument for the utility of testing can be made based upon the potential impact on treatment options, the ability to provide prognostic information, and the psychological, medical, and reproductive implications for patients and their family members. Clinicians who incorporate genetic testing into their evalua- tion of patients with epilepsy must be knowledgeable about epilepsy phenotypes and epilepsy genes, have expertise in eliciting a genetic family history that encompasses not only epilepsy but a broader range of relevant medical conditions, and possess a thor- ough understanding of genetic testing methods and outcomes. Given the complexity of genetic test results, it is crucial that informed consent to discuss the risks, benefits, and limitations of genetic testing take place with patients prior to testing. In addi- tion, many patients may benefit from genetic counseling to discuss testing options or results, address family impact or reproductive issues, and obtain access to support resources.

SCN1A variants associated with sudden infant death syndrome

We identified SCN1A variants in 2 infants who died of sudden infant death syndrome (SIDS) with hippocampal abnormalities from an exome sequencing study of 10 cases of SIDS but no history of seizures. One harbored SCN1A G682V, and the other had 2 SCN1A variants in cis: L1296M and E1308D, a variant previously associated with epilepsy. Functional evaluation in a heterologous expression system demonstrated partial loss of function for both G682V and the compound variant L1296M/E1308D. Our cases represent a novel association between SCN1A and SIDS, extending the SCN1A spectrum from epilepsy to SIDS. Our findings provide insights into SIDS and support genetic evaluation focused on epilepsy genes in SIDS.

Variability Among Next-Generation Sequencing Panels for Early-Life Epilepsies

Variability Among Next-Generation Sequencing Panels for Early-Life Epilepsies Epilepsy genetics is an emerging field with increasing therapeutic implications resulting from genetic findings.1 Despite an overall enthusiasm for precision medicine in epilepsy and other disciplines, there remains no consensus on the approach to genetic testing.2 A recent study by Berg et al3 demonstrated a relatively similar diagnostic yield of epilepsy next-generation sequencing (NGS) gene panels compared with whole-exome sequencing (27% vs 33%). Although the utility of NGS panels are consistently demonstrated,3,4 to our knowledge, no study has systematically evaluated the variability in genes tested among clinically available NGS panels. We compared the potential diagnostic yield of commercially available NGS epilepsy panels to detect the genetic findings identified in a recently published cohort of early-life epilepsy.3

PCDH19-related epilepsy is associated with a broad neurodevelopmental spectrum

To characterize the features associated with PCDH19‐related epilepsy, also known as “female‐limited epilepsy.”

Genetics of Epilepsy in the Era of Precision Medicine: Implications for Testing, Treatment, and Genetic Counseling

Purpose of ReviewEpilepsy is among the most common neurological diseases, affecting 65 million people worldwide. Recent revisions to the classification of epilepsies by the International League Against Epilepsy (ILAE) reflect a growing awareness of genetic contributions to epilepsy. Research in epilepsy genetics has begun to look beyond gene discovery to the horizon of genotype-driven precision medicine.Recent FindingsDuring the past 5xa0years, the advent of next-generation sequencing has led to exponential growth in the discovery of epilepsy-related genes. The yield of clinically available genetic tests for patients with epilepsy may be as high as 50%, particularly among patients with early-onset epileptic encephalopathy (EOEE). Among patients with early-life epilepsies who have a genetic diagnosis, de novo pathogenic variants are most frequently observed, and rates of somatic mosaicism among both patients and parents are higher than initially anticipated. Phenotypic heterogeneity is quite broad for many epilepsy-related genes, and genotype-phenotype correlations continue to prove complex and at times challenging.SummaryWith a focus on early-life epilepsies, we review recent highlights from the literature regarding gene discovery, approaches to and outcomes of clinical genetic evaluation, and contemporary efforts toward precision treatment. We also address genetic counseling issues of relevance for this population.

A Recurrent De Novo PACS2 Heterozygous Missense Variant Causes Neonatal-Onset Developmental Epileptic Encephalopathy, Facial Dysmorphism, and Cerebellar Dysgenesis

Developmental and epileptic encephalopathies (DEEs) represent a large clinical and genetic heterogeneous group of neurodevelopmental diseases. The identification of pathogenic genetic variants in DEEs remains crucial for deciphering this complex group and for accurately caring for affected individuals (clinical diagnosis, genetic counseling, impacting medical, precision therapy, clinical trials, etc.). Whole-exome sequencing and intensive data sharing identified a recurrent de novo PACS2 heterozygous missense variant in 14 unrelated individuals. Their phenotype was characterized by epilepsy, global developmental delay with or without autism, common cerebellar dysgenesis, and facial dysmorphism. Mixed focal and generalized epilepsy occurred in the neonatal period, controlled with difficulty in the first year, but many improved in early childhood. PACS2 is an important PACS1 paralog and encodes a multifunctional sorting protein involved in nuclear gene expression and pathway traffic regulation. Both proteins harbor cargo(furin)-binding regions (FBRs) that bind cargo proteins, sorting adaptors, and cellular kinase. Compared to the defined PACS1 recurrent variant series, individuals with PACS2 variant have more consistently neonatal/early-infantile-onset epilepsy that can be challenging to control. Cerebellar abnormalities may be similar but PACS2 individuals exhibit a pattern of clear dysgenesis ranging from mild to severe. Functional studies demonstrated that the PACS2 recurrent variant reduces the ability of the predicted autoregulatory domain to modulate the interaction between the PACS2 FBR and client proteins, which may disturb cellular function. These findings support the causality of this recurrent dexa0novo PACS2 heterozygous missense in DEEs with facial dysmorphim and cerebellar dysgenesis.