Epilepsy in patients with familial hemiplegic migraine

Is there a biochemical basis for purinergic P2X3 and P2X4 receptor antagonists to be considered as anti-seizure medications?

Patients with epilepsy require improved medications. Purinergic receptors were identified as late as 1976 and are slowly emerging as potential drug targets for the discovery of antiseizure medications. While compounds interacting with these receptors have been approved for use as medicines (e.g., gefapixant for cough) and continue to be explored for a number of diseases (e.g., pain, cancer), there have been no purinergic receptor antagonists that have been advanced for epilepsy. There are very few studies on the channel conducting receptors, P2X3 and P2X4, that suggest their possible role in seizure generation or control. However, the limited data available provides some compelling reasons to believe that they could be valuable antiseizure medication drug targets. The data implicating P2X3 and P2X4 receptors in epilepsy includes the role played by ATP in neuronal excitability and seizures, receptor localization, increased receptor expression in epileptic brain, the involvement of these receptors in seizure-associated inflammation, crosstalk between these purinergic receptors and neuronal processes involved in seizures (GABAergic and glutamatergic neurotransmission), and the significant attenuation of seizures and seizure-like activity with P2X receptor blockade. The discovery of new and selective antagonists for P2X3 and P2X4 receptors is ongoing, armed with new structural data to guide rational design. The availability of safe, brain-penetrant compounds will likely encourage the clinical exploration of epilepsy as a disease entity.

Exome data of developmental and epileptic encephalopathy patients reveals de novo and inherited pathologic variants in epilepsy-associated genes

PURPOSE

In Developmental and Epileptic Encephalopathies (DEEs), identifying the precise genetic factors guides the clinicians to apply the most appropriate treatment for the patient. Due to high locus heterogeneity, WES analysis is a promising approach for the genetic diagnosis of DEE. Therefore, the aim of the present study is to evaluate the utility of WES in the diagnosis and treatment of DEE patients.

METHODS

The exome data of 29 DEE patients were filtrated for destructive and missense mutations in 1896 epilepsy-related genes to detect the causative variants and examine the genotype-phenotype correlations. We performed Sanger sequencing with the available DNA samples to follow the co-segregation of the variants with the disease phenotype in the families. Also, the structural effects of p.Asn1053Ser, p.Pro120Ser and p.Glu1868Gly mutations on KCNMA1, NPC2, and SCN2A proteins, respectively, were evaluated by molecular dynamics (MD) and molecular docking simulations.

RESULTS

Out of 29, nine patients (31%) harbor pathological (P) or likely pathological (LP) mutations in SCN2A, KCNQ2, ATP1A2, KCNMA1, and MECP2 genes, and three patients have VUS variants (10%) in SCN1A and SCN2A genes. Sanger sequencing results indicated that three of the patients have de novo mutations while eight of them carry paternally and/or maternally inherited causative variants. MD and molecular docking simulations supported the destructive effects of the mutations on KCNMA1, NPC2, and SCN2A protein structures.

CONCLUSION

Herein we demonstrated the effectiveness of WES for DEE with high locus heterogeneity. Identification of the genetic etiology guided the clinicians to adjust the proper treatment for the patients.

Familial hemiplegic migraine type 2: a case report of an adolescent with ATP1A2 mutation

This study presents a case report of a male adolescent diagnosed with familial hemiplegic migraine type 2 (FHM2), an autosomal dominant inheritance disorder caused by ATP1A2 mutation. We report the patient who presented with headache, aphasia, and left-sided weakness. Cerebrovascular disease and various infectious agents were unremarkable during the patient's extended hospital stay. Our case revealed that brain hyperperfusion in familial hemiplegic migraine (FHM) persists over an extended duration, and despite the disease being in a state of recovery, enhanced brain magnetic resonance imaging (MRI) continues to exhibit hyperperfusion. A genetic testing was performed which revealed a mutation in the FHM2 gene (c.1133C > T). The patient has been followed for 3 years after hospital discharge. The boy suffered four episodes of hemiplegia and multiple episodes of headaches, and gradually developed seizures and cognitive impairment. It is advisable to consider FHM as a potential diagnosis for patients presenting with typical symptoms such as recurrent paroxysmal headaches and limb activity disorders.

Migraine - a borderland disease to epilepsy: near it but not of it

BACKGROUND

Migraine and epilepsy are two paroxysmal chronic neurological disorders affecting a high number of individuals and being responsible for a high individual and socioeconomic burden. The link between these disorders has been of interest for decades and innovations concerning diagnosing and treatment enable new insights into their relationship.

FINDINGS

Although appearing to be distinct at first glance, both diseases exhibit a noteworthy comorbidity, shared pathophysiological pathways, and significant overlaps in characteristics like clinical manifestation or prophylactic treatment. This review aims to explore the intricate relationship between these two conditions, shedding light on shared pathophysiological foundations, genetic interdependencies, common and distinct clinical features, clinically overlapping syndromes, and therapeutic similarities. There are several shared pathophysiological mechanisms, like CSD, the likely underlying cause of migraine aura, or neurotransmitters, mainly Glutamate and GABA, which represent important roles in triggering migraine attacks and seizures. The genetic interrelations between the two disorders can be observed by taking a closer look at the group of familial hemiplegic migraines, which are caused by mutations in genes like CACNA1A, ATP1A2, or SCN1A. The intricate relationship is further underlined by the high number of shared clinical features, which can be observed over the entire course of migraine attacks and epileptic seizures. While the variety of the clinical manifestation of an epileptic seizure is naturally higher than that of a migraine attack, a distinction can indeed be difficult in some cases, e.g. in occipital lobe epilepsy. Moreover, triggering factors like sleep deprivation or alcohol consumption play an important role in both diseases. In the period after the seizure or migraine attack, symptoms like speech difficulties, tiredness, and yawning occur. While the actual attack of the disease usually lasts for a limited time, research indicates that individuals suffering from migraine and/or epilepsy are highly affected in their daily life, especially regarding cognitive and social aspects, a burden that is even worsened using antiseizure medication. This medication allows us to reveal further connections, as certain antiepileptics are proven to have beneficial effects on the frequency and severity of migraine and have been used as a preventive drug for both diseases over many years.

CONCLUSION

Migraine and epilepsy show a high number of similarities in their mechanisms and clinical presentation. A deeper understanding of the intricate relationship will positively advance patient-oriented research and clinical work.

Developing a pathway to clinical trials for CACNA1A-related epilepsies: A patient organization perspective

CACNA1A-related disorders are rare neurodevelopmental disorders linked to variants in the CACNA1A gene. This gene encodes the α1 subunit of the P/Q-type calcium channel Cav2.1, which is globally expressed in the brain and crucial for fast synaptic neurotransmission. The broad spectrum of CACNA1A-related neurological disorders includes developmental and epileptic encephalopathies, familial hemiplegic migraine type 1, episodic ataxia type 2, spinocerebellar ataxia type 6, together with unclassified presentations with developmental delay, ataxia, intellectual disability, autism spectrum disorder, and language impairment. The severity of each disorder is also highly variable. The spectrum of CACNA1A-related seizures is broad across both loss-of-function and gain-of-function variants and includes absence seizures, focal seizures with altered consciousness, generalized tonic-clonic seizures, tonic seizures, status epilepticus, and infantile spasms. Furthermore, over half of CACNA1A-related epilepsies are refractory to current therapies. To date, almost 1700 CACNA1A variants have been reported in ClinVar, with over 400 listed as Pathogenic or Likely Pathogenic, but with limited-to-no clinical or functional data. Robust genotype-phenotype studies and impacts of variants on protein structure and function have also yet to be established. As a result, there are few definitive treatment options for CACNA1A-related epilepsies. The CACNA1A Foundation has set out to change the landscape of available and effective treatments and improve the quality of life for those living with CACNA1A-related disorders, including epilepsy. Established in March 2020, the Foundation has built a robust preclinical toolbox that includes patient-derived induced pluripotent stem cells and novel disease models, launched clinical trial readiness initiatives, and organized a global CACNA1A Research Network. This Research Network is currently composed of over 60 scientists and clinicians committed to collaborating to accelerate the path to CACNA1A-specific treatments and one day, a cure.

A comparison of comorbid headache between patients with temporal lobe epilepsy and juvenile myoclonic epilepsy

Headache is one of the most common symptoms of epilepsy comorbidities. However, the relationship between the epilepsy and headache still needs clarification. Previous studies mostly investigated the overall incidence and clinical features of the headache in patients with the epilepsy. Temporal lobe epilepsy (TLE) and juvenile myoclonic epilepsy (JME) are the common types of focal epilepsy and generalized epilepsy, respectively. Nevertheless, there was no study comparing the clinical features of headache between TLE and JME. This study aimed to analyze the headache features of these two types of epilepsy. Patients with either TLE or JME diagnosed with headache and referred to the West China Hospital of Sichuan University were consecutively recruited from June 2021 to June 2022. The duration of epilepsy was longer than 6 months in these patients. Data on headache and epilepsy were obtained through face-to-face questionnaires. The headache was classified according to the International Classification Headache Disorders-3rd edition (ICHD-III) criteria. χ2-test, t-test, rank-sum test, logistic regression modeling and Mann Whitney test were used to compare the clinical differences of the headache in TLE and JME. A total of 151 TLE patients and 30 JME patients were enrolled in this study. There was no significant difference in the family history of headache, epilepsy durations, headache types, proportion receiving analgesic therapy, the frequency of inter-ictal headache (inter-IH), and the quality of life in epilepsy -10 inventory (QOLIE-10) between the TLE and JME patients. Patients in the TLE group were significantly older (p = 0.004), and a lower percentage of them had a family history of epilepsy (p = 0.007) compared with the JME patients. The proportion of cases with refractory epilepsy was higher in the TLE group than that in the JME group (p < 0.001). The types of seizures in the TLE group varied from those in the JME group (p < 0.001). The composition of the antiseizure medications (ASM) applied in the TLE group differed from that in the JME group (p = 0.047), and the usage of oxcarbazepine was more frequently in the TLE group than in the JME group (p = 0.003). There was no difference in the headache types among patients with TLE or JME. Specifically, 67 (44.37%), 12 (7.95%), and 118 (7.95%) patients were found with inter-IH, pre-ictal headache (Pre-IH) and post-ictal headache (Post-IH) in the TLE group; while 8 (26.67%), 4 (13.33%) and 26 (86.67%) patients had inter-IH, Pre-IH and Post-IH in the JME group. Thirty-nine patients in the TLE group and 4 patients in the JME group were identified with more than one type of headaches, respectively. Tension-type headache (TTH) were found in 38 patients (25.17%) in the TLE group and 3 patients (10.00%) in the JME group, respectively; migraines were found in 10 patients (6.62%) in the TLE group and in 2 patients (6.67%) in the JME group. Patients in the TLE group had a higher headache-attributed lost time-90 days (HLT-90) score than those in the JME group (p = 0.019). The proportion of patients with inter-IH accompanied by nausea in the TLE group was higher than that in the JME group (p = 0.029), while the proportion of patients with frontal headache was lower than that in the JME group (p < 0.05). There was no significant difference in headache severity, quality, headache nature, unilateral/bilateral, and headache duration either in inter-IH or peri-ictal headache (Peri-IH) between the two groups. The logistic regression analysis suggested that except for HLT-90 (AUC = 0.622, p = 0.027), other factors were not found to be correlated with refractory epilepsy. The clinical features of headache differed between TLE and JME patients. TLE patients had a higher ratio of refractory epilepsy, more headache time loss compared with JME patients. HLT-90 was associated with the occurrence of refractory epilepsy in TLE patients. Taken together, we suggested that the comorbid headache may essentially be different between TLE and JME patients.

Neurological and psychiatric comorbidities of migraine: Concepts and future perspectives

BACKGROUND

This narrative review aims to discuss several common neurological and psychiatric disorders that show comorbidity with migraine. Not only can we gain pathophysiological insights by studying these disorders, comorbidities also have important implications for treating migraine patients in clinical practice.

METHODS

A literature search on PubMed and Embase was conducted with the keywords "comorbidity", "migraine disorders", "migraine with aura", "migraine without aura", "depression", "depressive disorders", "epilepsy", "stroke", "patent foramen ovale", "sleep wake disorders", "restless legs syndrome", "genetics", "therapeutics".

RESULTS

Several common neurological and psychiatric disorders show comorbidity with migraine. Major depression and migraine show bidirectional causality and have shared genetic factors. Dysregulation of both hypothalamic and thalamic pathways have been implicated as a possibly cause. The increased risk of ischaemic stroke in migraine likely involves spreading depolarizations. Epilepsy is not only bidirectionally related to migraine, but is also co-occurring in monogenic migraine syndromes. Neuronal hyperexcitability is an important overlapping mechanism between these conditions. Hypothalamic dysfunction is suggested as the underlying mechanism for comorbidity between sleep disorders and migraine and might explain altered circadian timing in migraine.

CONCLUSION

These comorbid conditions in migraine with distinct pathophysiological mechanisms have important implications for best treatment choices and may provide clues for future approaches.

Genetics of migraine: where are we now?

Migraine is a complex brain disorder explained by the interaction of genetic and environmental factors. In monogenic migraines, including familial hemiplegic migraine and migraine with aura associated with hereditary small-vessel disorders, the identified genes code for proteins expressed in neurons, glial cells, or vessels, all of which increase susceptibility to cortical spreading depression. The study of monogenic migraines has shown that the neurovascular unit plays a prominent role in migraine. Genome-wide association studies have identified numerous susceptibility variants that each result in only a small increase in overall migraine risk. The more than 180 known variants belong to several complex networks of "pro-migraine" molecular abnormalities, which are mainly neuronal or vascular. Genetics has also highlighted the importance of shared genetic factors between migraine and its major co-morbidities, including depression and high blood pressure. Further studies are still needed to map all of the susceptibility loci for migraine and then to understand how these genomic variants lead to migraine cell phenotypes.

Bioinformatics and network pharmacology analysis of drug targets and mechanisms related to the comorbidity of epilepsy and migraine

OBJECTIVE

The present study aimed to explore the mechanisms underlying the comorbidity of epilepsy and migraine, identify potential common targets for drug intervention, and provide insight into new avenues for disease prevention and treatment using an integrated bioinformatic and network pharmacology approach.

METHODS

Disease targets in epilepsy and migraine were screened using the DisGeNET database to identify intersecting gene targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) enrichment analyses were then performed using the WebGestalt database. Furthermore, the STRING database was used to construct a protein-protein interaction (PPI) network, and Cytoscape software was used to analyze the protein molecular signals at the intersection of epilepsy and migraine. The Drugbank database was used to identify common targets for antiepileptic drugs in epilepsy and migraine to further analyze the disease-gene-target-drug interaction network. Finally, molecular docking simulations were performed to verify the hypothesis that migraine and epilepsy share common diseases and drug targets.

RESULTS

A total of 178 common targets for epilepsy and migraine were identified using the DisGeNET database, and the 24 genes most related to the diseases were screened using the Score_gda gene scoring system. GO enrichment analysis indicated that common targets were mainly enriched in biological processes and molecular functions, including membrane potential regulation, inorganic ion transmembrane transport, axonal signaling, and ion channel activity. KEGG pathway enrichment analysis indicated that the mechanism of action might be related to neuroactive ligand receptors, AGE-RAGE, cAMP, and VEGF signaling pathways. The PPI network construction and analysis results showed that the PPI grid had 23 central nodes and 24 connected edges, with an average node degree of 2.09 and an average clustering coefficient of 0.384. The 10 genes with potentially important roles in epilepsy and migraine were CACNA1A, KCNQ2, KCNA1, SCN1A, PRRT2, SCN8A, KCNQ3, SCN2A, GRIN2A, and GABRG2. Drugbank database results indicated that antiepileptic drugs, including lamotrigine, topiramate, valproic acid, carbamazepine, gabapentin, and perampanel, also had common targets with migraine. The three most important targets exhibited strong binding affinity with drugs in the molecular docking simulations.

CONCLUSION

Our systematic and comprehensive analyses of disease-gene-target-drug interaction networks identified several biological processes and molecular functions common to migraine and epilepsy, most of which were related to neuroactive ligand-receptor interactions. These data provide a new theoretical basis and reference for the clinical treatment of comorbid epilepsy and migraine and may aid in the development of novel pharmacological strategies.

Migraine with aura

This chapter describes the different types of aura including rare aura subtypes such as retinal aura. In addition, aura manifestations not classified in the International Classification of Headache Disorders and auras in headache disorders others than migraine are also described. The differential diagnosis of migraine aura comprises several neurological disorders which should be known to specialists. Migraine aura also has impact on the choice of migraine treatment; recommendations for the treatment of the migraine aura itself are also presented in this chapter.

The ATP1A2 Mutation Associated with Hemiplegic Migraines: Case Report and Literature Review

Familial hemiplegic migraine type 2 is a premonitory subtype of migraine caused by an ATP1A2 gene mutation. It is an autosomal dominant genetic disease. Here, we report a 51-year-old woman who had a migraine attack due to a pathogenic ATP1A2 gene mutation. With frequent attacks, the patient developed complete left hemiplegia, a confusion of consciousness and partial seizures. Magnetic resonance imaging showed extensive angiogenic edema in the right cerebral hemisphere. In this article, we review the latest literature and try to explain the above symptoms in our patient with cortical spreading depression (CSD) and ATP1A2 gene mutations.

SCN1A-Related Epilepsy: Novel Mutations and Rare Phenotypes

Objectives

To expand the genotypes and phenotypes of sodium voltage-gated channel alpha subunit 1 (SCN1A)-related epilepsy.

Methods

We retrospectively collected the clinical and genetic information of 22 epilepsy patients (10 males, 12 females; mean: 9.2 ± 3.9 years; 3.9–20.3 years) carrying 22 variants of SCN1A. SCN1A mutations were identified by next-generation sequencing.

Results

Twenty-two variants were identified, among which 12 have not yet been reported. The median age at seizure onset was 6 months. Sixteen patients were diagnosed with Dravet syndrome (DS), two with genetic epilepsy with febrile seizures plus [one evolved into benign epilepsy with centrotemporal spikes (BECTS)], one with focal epilepsy, one with atypical childhood epilepsy with centrotemporal spikes (ABECTS) and two with unclassified epilepsy. Fourteen patients showed a global developmental delay/intellectual disability (GDD/ID). Slow background activities were observed in one patient and epileptiform discharges were observed in 11 patients during the interictal phase.

Significance

This study enriches the genotypes and phenotypes of SCN1A-related epilepsy. The clinical characteristics of patients with 12 previously unreported variants were described.

Headache in idiopathic/genetic epilepsies: Cluster analysis in a large cohort

OBJECTIVES

The link between headache and epilepsy is more prominent in patients with idiopathic/genetic epilepsy (I/GE). We aimed to investigate the prevalence of headache and to cluster patients with regard to their headache and epilepsy features.

METHODS

Patients aged 6-40 years, with a definite diagnosis of I/GE, were consecutively enrolled. The patients were interviewed using standardized epilepsy and headache questionnaires and their headache characteristics were investigated by experts in headache. Demographic and clinical variables were analyzed and patients were clustered according to their epilepsy and headache characteristics using an unsupervized K-means algorithm.

RESULTS

Among 809 patients, 508 (62.8%) reported having any type of headache; 87.4% had interictal headache and 41.2% had migraine. Cluster analysis revealed two distinct groups for both adults and children/adolescents. In adults, having a family history of headache, ≥5 headache attacks, duration of headache ≥24 months, headaches lasting ≥ 1 hour, and visual analog scale scores >5 were grouped in one cluster, and juvenile myoclonic epilepsy (JME), myoclonic, and generalized tonic-clonic seizures (GTCS) were clustered in this group (cluster 1). Self-limited epilepsy with centro-temporal spikes and epilepsy with GTCS alone were clustered in cluster 2 with the opposite characteristics. For children/adolescents, the same features as in adult cluster 1 were clustered in a separate group, except for the presence of JME syndrome and GTCS alone as a seizure type. Focal seizures were clustered in another group with the opposite characteristics. In the entire group, the model revealed an additional cluster, including patients with the syndrome of GTCS-alone (50.51%), with ≥ 5 attacks, headache lasting >4 hours, and throbbing headache; 65.66% of patients had a family history of headache in this third cluster (n=99).

SIGNIFICANCE

Patients with I/GE can be clustered into distinct groups according to headache features along with seizures. Our findings may help in management and planning for future studies.

Functional correlation of ATP1A2 mutations with phenotypic spectrum: from pure hemiplegic migraine to its variant forms

Background

Mutations in ATP1A2, the gene encoding the α2 subunit of Na⁺/K⁺-ATPase, are the main cause of familial hemiplegic migraine type 2 (FHM2). The clinical presentation of FHM2 with mutations in the same gene varies from pure FHM to severe forms with epilepsy and intellectual disability, but the correlation of these symptoms with different ATP1A2 mutations is still unclear.

Methods

Ten ATP1A2 missense mutations were selected according to different phenotypes of FHM patients. They caused pure FHM (FHM: R65W, R202Q, R593W, G762S), FHM with epilepsy (FHME: R548C, E825K, R938P), or FHM with epilepsy and intellectual disability (FHMEI: T378N, G615R, D718N). After ouabain resistance and fluorescence modification, plasmids carrying those mutations were transiently transfected into HEK293T and HeLa cells. The biochemical functions were studied including cell survival assays, membrane protein extraction, western blotting, and Na⁺/K⁺-ATPase activity tests. The electrophysiological functions of G762S, R938P, and G615R mutations were investigated in HEK293T cells using whole-cell patch-clamp. Homology modeling was performed to determine the locational distribution of ATP1A2 mutations.

Results

Compared with wild-type pumps, all mutations showed a similar level of protein expression and decreased cell viability in the presence of 1 µM ouabain, and there was no significant difference among the mutant groups. The changes in Na⁺/K⁺-ATPase activity were correlated with the severity of FHM phenotypes. In the presence of 100 µM ouabain, the Na⁺/K⁺-ATPase activity was FHM > FHME > FHMEI. The ouabain-sensitive Na⁺/K⁺-ATPase activity of each mutant was significantly lower than that of the wild-type protein, and there was no significant difference among all mutant groups. Whole-cell voltage-clamp recordings in HEK293T cells showed that the ouabain-sensitive pump currents of G615R were significantly reduced, while those of G762S and R938P were comparable to those of the wild-type strain.

Conclusions

ATP1A2 mutations cause phenotypes ranging from pure FHM to FHM with epilepsy and intellectual disability due to varying degrees of deficits in biochemical and electrophysiological properties of Na⁺/K⁺-ATPase. Mutations associated with intellectual disability presented with severe impairment of Na⁺/K⁺-ATPase. Whether epilepsy is accompanied, or the type of epilepsy did not seem to affect the degree of impairment of pump function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01309-4.

Relationships between migraine and epilepsy: Pathophysiological mechanisms and clinical implications

Migraine and epilepsy are distinct neurological diseases with specific clinical features and underlying pathophysiological mechanisms. However, numerous studies have highlighted the complex and multifaceted relationships between the two conditions. The relationships between headache and epilepsy manifest themselves in different ways. Firstly, the clinical diagnosis of these disorders may be challenging in view of possible overlapping. While post-ictal headache is a frequent condition, ictal epileptic headache is a rare but challenging diagnosis. Both situations raise the question of the pathophysiological mechanism of headache triggered by seizures. Migraine aura and epilepsy can also exhibit overlapping symptoms leading to their misdiagnosis, in particular in the case of visual aura. Secondly, migraine with aura and epilepsy can occur as a co-morbid condition, particularly in familial hemiplegic migraine (FHM). From a pathophysiological perspective, the identification of genetic mutations in FHM has brought significant advances in the understanding of dysfunctions of neuronal networks leading to hyperexcitability. The purpose of this review is to present clinical situations encompassing headache and epilepsy that can be challenging in neurological practice and to discuss the underlying pathophysiological mechanism of such interactions.