Neurological disorder-associated genetic variants in individuals with psychogenic nonepileptic seizures

Electro-Clinical Features and Functional Connectivity Analysis in SYN1-Related Epilepsy

OBJECTIVE

There is currently scarce data on the electroclinical characteristics of epilepsy associated with synapsin 1 (SYN1) pathogenic variations. We examined clinical and electro-encephalographic (EEG) features in patients with epilepsy and SYN1 variants, with the aim of identifying a distinctive electroclinical pattern.

METHODS

In this retrospective multicenter study, we collected and reviewed demographic, genetic, and epilepsy data of 19 male patients with SYN1 variants. Specifically, we analyzed interictal EEG data for all patients, and electro-clinical data from 10 epileptic seizures in 5 patients, using prolonged video-EEG monitoring recordings. Inter-ictal EEG functional connectivity parameters and frequency spectrum of the 10 patients over 12 years of age, were computed and compared with those of 56 age- and sex-matched controls.

RESULTS

The main electroclinical features of epilepsy in patients with SYN1 were (1) EEG background and organization mainly normal; (2) interictal abnormalities are often rare or not visible on EEG; (3) more than 60% of patients had reflex seizures (cutaneous contact with water and defecation being the main triggers) isolated or associated with spontaneous seizures; (4) electro-clinical semiology of seizures was mainly temporal or temporo-insulo/perisylvian with a notable autonomic component; and (5) ictal EEG showed a characteristic rhythmic theta/delta activity predominating in temporo-perisylvian regions at the beginning of most seizures. Comparing patients with SYN1 to healthy subjects, we observed a shift to lower frequency bands in power spectrum of interictal EEG and an increased connectivity in both temporal regions.

INTERPRETATION

A distinct epilepsy syndrome emerges in patients with SYN1, with a rather characteristic clinical and EEG pattern suggesting predominant temporo-insular involvement. ANN NEUROL 2024.

Polymorphism of glucocorticoid receptor gene (rs41423247) in functional seizures (psychogenic nonepileptic seizures/attacks)

OBJECTIVE

We investigated the association between the glucocorticoid receptor (GR) gene, also known as the nuclear receptor subfamily 3, group C, member 1 (NR3C1), rs41423247 polymorphism, and functional seizures (psychogenic nonepileptic seizures/attacks) in a case-control study. We hypothesized that the tested polymorphism has significant associations with functional seizures (psychogenic nonepileptic seizures/attacks) independent from comorbid depression.

METHODS

Seventy patients with functional seizures (psychogenic nonepileptic seizures/attacks), 70 with major depressive disorder (MDD), and 70 healthy controls (HCs) were studied. Their DNAs were analyzed for NR3C1 rs41423247 polymorphism.

RESULTS

Genotype and allele frequencies of rs41423247 were different between the three groups. G allele carriers were more frequent in patients with functional seizures (psychogenic nonepileptic seizures/attacks) and those with MDD compared to HCs (p = 0.0001). However no significant difference was observed with respect to allele distributions between functional seizures (psychogenic nonepileptic seizures/attacks) and MDD groups (p = 0.391). CC genotype was less often associated with functional seizures (psychogenic nonepileptic seizures/attacks) versus HC: Codominant model; p = 0.001, OR = 0.11, 95% CI = 0.05-0.24, and -2loglilkelihood = 231.7. In comparison between functional seizures (psychogenic nonepileptic seizures/attacks) group and other (MDD + HC) groups, we observed a significant association between CG genotype and functional seizures (psychogenic nonepileptic seizures/attacks) (Codominant model; p = 0.001, OR = 5.63, 95% CI = 2.60-12.40 and -2loglikelihood = 245.99).

SIGNIFICANCE

Patients with functional seizures (psychogenic nonepileptic seizures/attacks) and those with MDD were significantly more often G allele carriers in rs41423247 compared with HCs. We observed a significant association between CG genotype and functional seizures (psychogenic nonepileptic seizures/attacks). However, we could not exclude the possibility of confounding effects of depression. Future genetic studies of patients with functional seizures (psychogenic nonepileptic seizures/attacks) should include a comparison group with depression in addition to a comparison group of HCs.

Genetics of Functional Seizures; A Scoping Systematic Review

BACKGROUND

Evidence on the genetics of functional seizures is scarce, and the purpose of the current scoping systematic review is to examine the existing evidence and propose how to advance the field.

METHODS

Web of science and MEDLINE were searched, from their initiation until May 2023. The following key words were used: functional neurological disorder(s), psychogenic neurological disorder(s), functional movement disorder(s), psychogenic movement disorder(s), functional seizures(s), psychogenic seizure(s), nonepileptic seizure(s), dissociative seizure(s), or psychogenic nonepileptic seizure(s), AND, gene, genetic(s), polymorphism, genome, epigenetics, copy number variant, copy number variation(s), whole exome sequencing, or next-generation sequencing.

RESULTS

We identified three original studies. In one study, the authors observed that six (5.9%) patients with functional seizures carried pathogenic/likely pathogenic variants. In another study, the authors observed that, in functional seizures, there was a significant correlation with genes that are over-represented in adrenergic, serotonergic, oxytocin, opioid, and GABA receptor signaling pathways. In the third study, the authors observed that patients with functional seizures, as well as patients with depression, had significantly different genotypes in FKBP5 single nucleotide polymorphisms compared with controls.

CONCLUSION

Future genetic investigations of patients with functional seizures would increase our understanding of the pathophysiological and neurobiological problems underlying this common neuropsychological stress-associated condition.

A systems biology approach for discovering the cellular and molecular aspects of psychogenic non-epileptic seizure

Objectives

Psychogenic non-epileptic seizure (PNES) is the most common non-epileptic disorder in patients referring to epilepsy centers. Contrary to common beliefs about the disease's harmlessness, the death rate of PNES patients is similar to drug-resistant epilepsy. Meanwhile, the molecular pathomechanism of PNES is unknown with very limited related research. Thus, the aim of this in silico study was to find different proteins and hormones associated with PNES via a systems biology approach.

Methods

Different bioinformatics databases and literature review were used to find proteins associated with PNES. The protein-hormone interaction network of PNES was constructed to discover its most influential compartments. The pathways associated with PNES pathomechanism were found by enrichment analysis of the identified proteins. Besides, the relationship between PNES-related molecules and psychiatric diseases was discovered, and the brain regions that could express altered levels of blood proteins were discovered.

Results

Eight genes and three hormones were found associated with PNES through the review process. Proopiomelanocortin (POMC), neuropeptide Y (NPY), cortisol, norepinephrine, and brain-derived neurotrophic factor (BDNF) were identified to have a high impact on the disease pathogenesis network. Moreover, activation of Janus kinase-signaling transducer and activator of transcription (JAK-STAT) and JAK, as well as signaling of growth hormone receptor, phosphatidylinositol 3-kinase /protein kinase B (PI3K/AKT), and neurotrophin were found associated with PNES molecular mechanism. Several psychiatric diseases such as depression, schizophrenia, and alcohol-related disorders were shown to be associated with PNES predominantly through signaling molecules.

Significance

This study was the first to gather the biochemicals associated with PNES. Multiple components and pathways and several psychiatric diseases associated with PNES, and some brain regions that could be altered during PNES were suggested, which should be confirmed in further studies. Altogether, these findings could be used in future molecular research on PNES patients.

Morphometric correlates in patients with functional seizures with and without comorbid epilepsy

OBJECTIVE

Functional seizures (FS) or psychogenic, non-epileptic seizures (PNES) are episodic alterations of behaviour with similar semiology to epileptic seizures but which are not caused by epileptic brain activity. Epilepsy patients show a high risk in developing FS; therefore, the purpose of this study is to examine morphometric correlates in patients with FS as well as in epilepsy patients with FS by comparing them separately to healthy controls (HC).

METHODS

Twenty-one clinical three-dimensional (3D) T1-magnetic resonance imaging (MRI) scans of patients with FS (FS group) and 15 patients with FS and epilepsy (EFS group) were retrospectively compared with one control group of 21 age- and gender-matched HC. Two separate general linear model analyses were conducted via FreeSurfer version 6.0.

RESULTS

The study population consisted of 21 FS patients (66.7% females, n = 14) with a median age at the time of the scan of 24 years (range 17-44 years); 15 EFS patients (80% females, n = 12) with a median age at the time of the scan of 27 years (range 16-43 years); and 21 healthy subjects (66.7% females, n = 14) with a median age at the time of the scan of 24 years (range 19-38 years). Both patient groups showed an increased Cth in the right prefrontal lobe: in the FS group in the right superior frontal, rostral middle frontal gyri and the right orbitofrontal cortex and, in the EFS group, in the right superior frontal gyrus and the right orbitofrontal cortex. Decreases in Cth were present in the right lateral occipital lobe in the FS group, while also in both hemispheres in the EFS group, namely the left paracentral, superior frontal, caudal middle frontal, lateral occipital and right superior frontal gyri. Neither group showed changes in curvature.

CONCLUSION

These results suggest alterations in regions of emotional processing and executive control in patients with FS regardless of the presence of epilepsy.

Expanding the phenotypic spectrum of KCNK4: From syndromic neurodevelopmental disorder to rolandic epilepsy

The KCNK4 gene, predominantly distributed in neurons, plays an essential role in controlling the resting membrane potential and regulating cellular excitability. Previously, only two variants were identified to be associated with human disease, facial dysmorphism, hypertrichosis, epilepsy, intellectual/developmental delay, and gingival overgrowth (FHEIG) syndrome. In this study, we performed trio-based whole exon sequencing (WES) in a cohort of patients with epilepsy. Two de novo likely pathogenic variants were identified in two unrelated cases with heterogeneous phenotypes, including one with Rolandic epilepsy and one with the FHEIG syndrome. The two variants were predicted to be damaged by the majority of in silico algorithms. These variants showed no allele frequencies in controls and presented statistically higher frequencies in the case cohort than that in controls. The FHEIG syndrome-related variants were all located in the region with vital functions in stabilizing the conductive conformation, while the Rolandic epilepsy-related variant was distributed in the area with less impact on the conductive conformation. This study expanded the genetic and phenotypic spectrum of KCNK4. Phenotypic variations of KCNK4 are potentially associated with the molecular sub-regional effects. Carbamazepine/oxcarbazepine and valproate may be effective antiepileptic drugs for patients with KCNK4 variants.

Genetic and molecular features of seizure-freedom following surgical resections for focal epilepsy: A pilot study

Objective

Seizure outcomes after brain surgery for drug-resistant epilepsy (DRE) are very heterogeneous and difficult to predict with models utilizing the current clinical, imaging, and electrophysiological variables. In this pilot study, we investigated whether genetic and molecular biomarkers (e.g., genomic, transcriptomic) can provide additional insight into differential response to surgery.

Methods

Post-operative seizure-outcomes were collected at last follow-up (>6 months) for 201 adult patients with DRE who underwent surgery between 2004 and 2020. Resected tissue was sent for miRNA sequencing (n = 132) and mRNA sequencing (n = 135). Following the selection of 10 genes (SCN1A, NBEA, PTEN, GABRA1, LGL1, DEPDC5, IL1A, ABCB1, C3, CALHM1), we investigated SNPs in those 10 genes from previously acquired exome sequencing data (n = 106). Logistic regression was performed to test for associations between individual features (mRNAs, miRNAs, and SNPs) and post-operative seizure-outcome with an exploratory FDR P < 0.25 as the threshold for significance. Post-operative time-to-seizure analyses were performed for each SNP using a Cox proportional hazards model.

Results

The majority of patients (83%) had temporal lobe epilepsy. Mean age at surgery was 38.3 years, and 56% were female. Three SNPs (rs10276036, rs11975994, rs1128503) in multi-drug resistance gene, ABCB1, were associated with post-operative seizure outcomes. Patients with alternate alleles in ABCB1 were more likely to be seizure-free at last follow-up (52–56% reduction in seizure recurrence; FDR P = 0.24). All three SNPs were in linkage disequilibrium and highly correlated with each other. Median post-operative time-to-seizure was 63 months for patients with 2 alternate alleles, 24–33 months with 1 alternate allele, and 10–11 months with 0 alternate alleles. These SNPs improved outcome prediction beyond MRI and sex alone. No independent miRNAs or mRNAs were significantly associated with seizure-outcome (P > 0.05). However, pathway analysis identified “cancer drug resistance by drug efflux” (mir-154 and mir-379) as enriched (P = 0.02), supporting the role of drug response genes in post-operative seizure recurrence.

Significance

ABCB1 may have a role in epileptogenesis and surgery outcomes independent of its drug efflux activity necessitating further investigation. SNPs in ABCB1 may serve as independent predictors of post-operative outcome.

Epilepsy and other seizure disorders in acute psychiatric inpatients

BACKGROUND

It is well known that patients with epilepsy have a high rate of psychiatric comorbidity. However, studies exploring epilepsy in psychiatric cohorts are scarce. The aim of this study was to examine the prevalence of seizure disorders in acute psychiatric inpatients.

METHODS

This is a cross-sectional study performed in a catchment-area based acute psychiatric department. All patients (age > 18) admitted during September 2011 - March 2012 were eligible for inclusion. Consenting patients were screened for a life-time history of epilepsy or seizures using self-reported questionnaire data and diagnostic codes for epilepsy in hospital and National registries. Patients scoring positive to one or more of these screening criteria underwent a thorough diagnostic validation (chart review), and the seizure disorders were classified as epilepsy, acute symptomatic seizures and/or psychogenic non-epileptic seizures according to current definitions.

RESULTS

A total of 380 out of 591 (64.3%) consecutively admitted patients consented to participate in the study. Eighty-nine patients (23.4%) scored positive to one or more screening criteria. Fifteen (3.9%) were classified with epilepsy, 21 (5.5%) with acute symptomatic seizures and 9 (2.4%) with psychogenic non-epileptic seizures.

CONCLUSIONS

This is the first study to report on the prevalence of seizure disorders in acute psychiatric inpatients. The life-time prevalence of epilepsy in this cohort of patients is five - six times as high as reports in the general population. These findings underscore the need for the clinical psychiatrist to have comprehensive knowledge on the interface between epileptology and psychiatry.

TRIALS REGISTRATION

ClinicalTrials.gov identifier NCT01415323 .

Is There a Characteristic Autonomic Response During Outbursts of Combative Behavior in Dementia Patients?

We sought to determine whether skin conductance level could warn of outbursts of combative behavior in dementia patients by using a wristband device. Two outbursts were captured and are reported here. Although no physiologic parameter measured by the wristband gave advance warning, there is a common pattern of parasympathetic withdrawal (increased heart rate) followed approximately 30 seconds later by sympathetic activation (increased skin conductance). In the literature, a similar pattern occurs in psychogenic non-epileptic seizures. We hypothesize that similar autonomic responses reflect similarities in pathophysiology and that physical activity may partially account for the time course of skin conductance.