Clinical and Genetic Profile of Autism Spectrum Disorder-Epilepsy (ASD-E) Phenotype: Two Sides of the Same Coin!

Identification of the Shared Gene Signatures between Autism Spectrum Disorder and Epilepsy via Bioinformatic Analysis

Purpose

To identify gene signatures that are shared by autism spectrum disorder (ASD) and epilepsy (EP) and explore the potential molecular mechanism of the two diseases using WGCNA analysis. Additionally, to verify the effects of the shared molecular mechanism on ADHD, which is another neurological comorbidity.

Methods

We screened the crosstalk genes between ASD and EP based on WGCNA and differential expression analysis from GEO and DisGeNET database and analyzed the function of the genes' enrichment by GO and KEGG analyses. Then, with combination of multiple datasets and multiple bioinformatic analysis methods, the shared gene signatures were identified. Moreover, we explored whether the shared gene signature had influence on the other neurological disorder like ADHD by analyzing the difference of the relative genes' expression based on bioinformatic analysis and molecular experiment.

Results

By comprehensive bioinformatic analysis for multiple datasets, we found that abnormal immune response and abnormal lipid metabolic pathway played important roles in coincidence of ASD and EP. Base on the results of WGCNA, we got the hub genes in ASD and EP. In attention deficit and hyperactivity disorder (ADHD) animal model, we also found a significant difference of gene expression related to sulfatide metabolism, indicating that the abnormal sphingolipid metabolism was common in multiple neurological disorders.

Conclusion

This study reveals shared gene signatures between ASD and EP and identifies abnormal sphingolipid metabolism as an important participant in the development of ASD, EP, and ADHD.

Epilepsy and EEG Abnormalities in Children with Autism Spectrum Disorders

OBJECTIVE

To evaluate the prevalence of epilepsy and  electroencephalographic abnormalities in children with autism spectrum disorders (ASD) and determine their risk factors.

METHODS

This cross-sectional study was conducted over one year in children with ASD aged between 3 and 14 y. Classification of epilepsy and routine electroencephalography (EEG) recordings were done for all the patients. Developmental and cognitive assessments were done using Developmental Profile 3. Children were divided into three groups: ASD with epilepsy, ASD with isolated electroencephalographic abnormalities, and ASD with neither epilepsy nor electroencephalographic abnormalities.

RESULTS

One hundred children with ASD were enrolled. Epilepsy was reported in 23% and subclinical electroencephalographic abnormalities were documented in 8%. The most common seizure types were generalized-onset tonic-clonic (48%), focal-onset with impaired awareness (17%), and focal to bilateral tonic-clonic seizures (17%). In children with subclinical epileptiform discharges, focal abnormalities were most common (75%) and were maximally seen over the temporal region (50%). Subnormal intellect (88.6%) and abnormal global developmental score (82%) were noted in the majority of children. Female gender, abnormal neurological examination, and adverse perinatal events were significantly associated with epilepsy. Of these, female gender and adverse perinatal events were independent predictors of epilepsy. Isolated EEG abnormalities were significantly associated with abnormal neurological examination in comparison with autistic children without epilepsy/EEG abnormalities.

CONCLUSION

Epilepsy is seen in up to one-fourth children with ASD. Female gender and adverse perinatal events are independent risk factors for epilepsy. Subclinical or isolated EEG abnormalities are associated with abnormal neurological examination.

Ketogenic and Low FODMAP Diet in Therapeutic Management of a Young Autistic Patient with Epilepsy and Dysmetabolism Poorly Responsive to Therapies: Clinical Response and Effects of Intestinal Microbiota

Autism spectrum disorder (ASD) is often associated with several intestinal and/or metabolic disorders as well as neurological manifestations such as epilepsy (ASD-E). Those presenting these neuropathological conditions share common aspects in terms of gut microbiota composition. The use of microbiota intervention strategies may be an approach to consider in the management of these cases. We describe the case of a 17-year-old girl affected by ASD, reduced growth, neurological development delay, mutations in the PGM1 and EEF1A2 genes (in the absence of clinically manifested disease) and, intestinal disorders such as abdominal pain and diarrhea associated with weight loss. As she demonstrated poor responsiveness to the therapies provided, we attempted two specific dietary patterns: a ketogenic diet, followed by a low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet, with the aim of improving her neurological, metabolic, and intestinal symptoms through modulation of the gut microbiota’s composition. The ketogenic diet (KD) provided a reduction in Firmicutes, Bacteroidetes, and Proteobacteria. Although her intestinal symptoms improved, KD was poorly tolerated. On the other hand, the passage to a low FODMAPs diet produced a significant improvement in all neurological, intestinal, and metabolic symptoms and was well-tolerated. The following gut microbiota analysis showed reductions in Actinobacteria, Firmicutes, Lactobacilli, and Bifidobacteria. The alpha biodiversity was consistently increased and the Firmicutes/Bacteroidetes ratio decreased, reducing the extent of fermentative dysbiosis. Gut microbiota could be a therapeutic target to improve ASD-related symptoms. Further studies are needed to better understand the correlation between gut microbiota composition and ASD, and its possible involvement in the physiopathology of ASD.

Knowledge Atlas of the Co-Occurrence of Epilepsy and Autism: A Bibliometric Analysis and Visualization Using VOSviewer and CiteSpace

OBJECTIVE

This study aimed to analyze research on epilepsy in autism and autism in epilepsy using VOSviewer and CiteSpace to identify research hotspots and future directions.

METHODS

We searched the Web of Science Core Collection (WoSCC) for relevant studies about epilepsy in autism and autism in epilepsy published from inception to 31 May 2022. VOSviewer and CiteSpace were used to analyze the authors, institutions, countries, publishing journals, reference co-citation patterns, keyword co-occurrence, keyword clustering, keywords with citation bursts, and other aspects to construct a knowledge atlas.

RESULTS

A total of 473 publications related to epilepsy/autism were retrieved. The number of publications about epilepsy/ASD has generally increased over time, with some fluctuations. The USA (202 papers) and University of California-Los Angeles (15 papers) were the leading country and institution, respectively, in this field. Frye, Richard E. was the most published author (9 papers). Notably, collaboration between institutions, countries, and authors does not appear to be active. Hot topics and research frontiers include intellectual disability and exploring the mechanism of epilepsy/ASD from a genetics perspective.

CONCLUSION

This analysis identified the most influential publications, authors, journals, institutions, and countries in the field of epilepsy/ASD research. Using co-occurrence and evolution analyses, the status of the field was identified and future trends were predicted.

The epilepsy-autism spectrum disorder phenotype in the era of molecular genetics and precision therapy

Autism spectrum disorder (ASD) is frequently associated with infants with epileptic encephalopathy, and early interventions targeting social and cognitive deficits can have positive effects on developmental outcome. However, early diagnosis of ASD among infants with epilepsy is complicated by variability in clinical phenotypes. Commonality in both biological and molecular mechanisms have been suggested between ASD and epilepsy, such as occurs with tuberous sclerosis complex. This review summarizes the current understanding of causal mechanisms between epilepsy and ASD, with a particularly genetic focus. Hypothetical explanations to support the conjugation of the two conditions include abnormalities in synaptic growth, imbalance in neuronal excitation/inhibition, and abnormal synaptic plasticity. Investigation of the probable genetic basis has implemented many genes, although the main risk supports existing hypotheses in that these cluster to abnormalities in ion channels, synaptic function and structure, and transcription regulators, with the mammalian target of rapamycin (mTOR) pathway and "mTORpathies" having been a notable research focus. Experimental models not only have a crucial role in determining gene functions but are also useful instruments for tracing disease trajectory. Precision medicine from gene therapy remains a theoretical possibility, but more contemporary developments continue in molecular tests to aid earlier diagnoses and better therapeutic targeting.

Genetic Testing in Pediatric Epilepsy

With the advent of next generation sequencing technology there has been a spurt of papers on genetics in epilepsy in children. Genetic testing has now become an essential part of clinical practice in epilepsy. It helps in reaching an etiological diagnosis, providing prognostic information, guiding therapy precisely indicated for the patient and avoiding drugs that may worsen the seizures. Once the pathogenic variant has been found, this enables determining and counseling the risk of recurrence to the patient and other relatives at risk. It also makes available different reproductive options such as prenatal diagnosis or pre-implantation diagnosis. The authors describe the benefits, the clinical situations that require genetic testing, the types of genetic tests that are available, and how to choose the appropriate test and their likely yields. Genetic counseling, both pre- and post-test that should be provided is described briefly. Two useful tables are included that depict the therapy for variants in different epilepsy genes.

Electroclinical Phenotype-Genotype Homogeneity in Drug-Resistant "Generalized" Tonic-Clonic Seizures of Early Childhood

PURPOSE

Children with refractory focal to bilateral tonic-clonic seizures, despite normal high-resolution imaging, are often not subjected to genetic tests due to the costs involved and instead undergo multimodality presurgical evaluation targeted at delineating a focal onset. The objective of this study was to ascertain genotype-phenotype correlations in this group of patients.

METHOD

An online hospital database search was conducted for children who presented in 2019 with drug-resistant epilepsy dominated by nonlateralizing focal-onset/rapid generalized (bilateral) tonic-clonic seizures (GTCS), subjected to presurgical evaluation and subsequent genetic testing due to absence of a clear focus hypothesis.

RESULTS

Phenotypic homogeneity was apparent in 3 children who had onset in infancy with drug-resistant GTCS (predominantly unprovoked and occasionally fever provoked) and subsequent delayed development. 3-Tesla magnetic resonance imaging (MRI) scans were negative and video EEG documented a homogeneous pattern of multifocal and/or generalized epileptiform discharges with phenomenology favoring probable focal-onset/generalized-onset bilateral tonic-clonic seizures. All 3 tested positive for SCN1A gene variants (heterozygous missense substitution variants in 2 children, one of which was novel and a novel duplication in one that led to frameshift and premature truncation of the protein), suggestive of SCN1A-mediated epilepsy. This electroclinical profile constituted 3 out of 25 patients with SCN1A-epilepsy phenotypes at our center.

CONCLUSIONS

These cases suggest that children with early-onset drug-resistant "generalized" epilepsy are likely to have a genetic basis although the presentation may not be typical of Dravet syndrome. Hence, genetic testing for SCN1A variants is recommended in children with drug-resistant MRI negative focal-onset/generalized-onset bilateral tonic-clonic seizures before subjecting them to exhaustive presurgical workup and to guide appropriate treatment and prognostication.