A novel inherited mutation in the voltage sensor region of SCN1A is associated with Panayiotopoulos syndrome in siblings and generalized epilepsy with febrile seizures plus

A Case Report of a 5-Year-Old Girl with Self-Limited Epilepsy with Autonomic Seizures

BACKGROUND

Self-limited epilepsy with autonomic seizures (SeLEAS), formerly known as Panayiotopoulos syndrome (PS), is a common multifocal autonomic childhood epileptic syndrome. SeLEAS affects 6% of children in between the ages of 1 and 15 years who have had one or more afebrile seizures in their lifetime.

CASE

A 5-year-old girl was admitted to the paediatric emergency room (ER) of our hospital due to a reported episode of vomiting during her sleep, followed by central cyanosis perorally of sort duration (<5'), a right turn of her head, and gaze fixation with right eye deviation. She was dismissed after a one-day hospitalization free of symptoms. A month later, the patient was admitted to the paediatric ER of a tertiary health unit due to a similar episode. The patient underwent EEG, which revealed pathologic paroxysmal abnormalities of high-amplitude sharp waves and spike-wave complexes in temporal-occipital areas of the left hemisphere, followed by enhancement of focal abnormalities in temporal-occipital areas of the left hemisphere during sleep. The patient was diagnosed with SeLEAS and started levetiracetam.

CONCLUSIONS

SeLEAS can be easily misdiagnosed as many physicians may not be very familiar with this disease, and, on the other hand, the autonomic manifestations can be easily disregarded as seizures. The physician must always be alert and search beneath the symptoms to find the cause rather than only treat them.

International League Against Epilepsy classification and definition of epilepsy syndromes with onset in childhood: Position paper by the ILAE Task Force on Nosology and Definitions

The 2017 International League Against Epilepsy classification has defined a three-tier system with epilepsy syndrome identification at the third level. Although a syndrome cannot be determined in all children with epilepsy, identification of a specific syndrome provides guidance on management and prognosis. In this paper, we describe the childhood onset epilepsy syndromes, most of which have both mandatory seizure type(s) and interictal electroencephalographic (EEG) features. Based on the 2017 Classification of Seizures and Epilepsies, some syndrome names have been updated using terms directly describing the seizure semiology. Epilepsy syndromes beginning in childhood have been divided into three categories: (1) self-limited focal epilepsies, comprising four syndromes: self-limited epilepsy with centrotemporal spikes, self-limited epilepsy with autonomic seizures, childhood occipital visual epilepsy, and photosensitive occipital lobe epilepsy; (2) generalized epilepsies, comprising three syndromes: childhood absence epilepsy, epilepsy with myoclonic absence, and epilepsy with eyelid myoclonia; and (3) developmental and/or epileptic encephalopathies, comprising five syndromes: epilepsy with myoclonic-atonic seizures, Lennox-Gastaut syndrome, developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, and febrile infection-related epilepsy syndrome. We define each, highlighting the mandatory seizure(s), EEG features, phenotypic variations, and findings from key investigations.

Panayiotopoulos syndrome: Unusual clinical manifestations

PURPOSE

We retrospectively analyzed the electroclinical features, treatment, and outcome of patients with Panayiotopoulos syndrome (PS) who presented with unusual clinical manifestations.

METHOD

A retrospective, descriptive, multicenter study was conducted evaluating 44 patients with PS who had seizures with an unusual semiology. Data from patients with PS seen at eight Argentine centers between April 2000 and April 2019 were collected.

RESULTS

Twelve patients (29.2%) had ictal syncope or syncope-like epileptic seizures. Three children (7.3%) had recurrent episodes of vomiting. Four patients (9.7%) presented with urinary incontinence associated with autonomic signs and consciousness impairment. One child had hiccups with autonomic manifestations followed by eye deviation. One boy had episodes of laughter with autonomic symptoms followed by loss of consciousness. Six patients (14.6%) had hyperthermia without acute febrile illness with autonomic symptoms as the first manifestation. Six others (14.6%) had focal motor seizures characterized by eye and head deviation in four and eyelid blinking in two. Four patients (9.7%) had ictal headache as the initial manifestation followed by nausea and vomiting. Two children (4.8%) had their first seizure while asleep associated with cardiorespiratory arrest. Two children (4.8%) had oral automatisms, such as sucking and chewing. In two children (4.8%) coughing was the initial manifestation followed by emetic symptoms. One patient (2.3%) had vertigo with a sensation of fear, with eye deviation and unresponsiveness. One child started with continuous spikes and waves during slow sleep, behavior disturbances, and emetic symptoms.

CONCLUSION

In this study, evidence of the existence of unusual clinical cases of PS with typical EEG patterns was found. Outcome was excellent.

SCN1A and Its Related Epileptic Phenotypes

Epilepsy is one of the most common neurological disorders, with a lifetime incidence of 1 in 26. Approximately two-thirds of epilepsy has a substantial genetic component in its etiology. As a result, simultaneous screening for mutations in multiple genes and performing whole exome sequencing (WES) are becoming very frequent in the clinical evaluation of children with epilepsy. In this setting, mutations in voltage-gated sodium channel (SCN) α-subunit genes are the most commonly identified cause of epilepsy, with sodium channel genes (i.e., SCN1A, SCN2A, SCN8A) being the most frequently identified causative genes. SCN1A mutations result in a wide spectrum of epilepsy phenotypes ranging from simple febrile seizures to Dravet syndrome, a severe epileptic encephalopathy. In case of mutation of SCN1A, it is also possible to observe behavioral alterations, such as impulsivity, inattentiveness, and distractibility, which can be framed in an attention deficit hyperactivity disorder (ADHD) like phenotype. Despite more than 1,200 SCN1A mutations being reported, it is not possible to assess a clear phenotype–genotype correlations. Treatment remains a challenge and seizure control is often partial and transitory.

Focal epilepsy in SCN1A-mutation carrying patients: is there a role for epilepsy surgery?

Variants in the gene SCN1A are a common genetic cause for a wide range of epilepsy phenotypes ranging from febrile seizures to Dravet syndrome. Focal onset seizures and structural lesions can be present in these patients and the question arises whether epilepsy surgery should be considered. We report eight patients (mean age 13y 11mo [SD 8y 1mo], range 3-26y; four females, four males) with SCN1A variants, who underwent epilepsy surgery. Outcomes were variable and seemed to be directly related to the patient's anatomo-electroclinical epilepsy phenotype. Patients with Dravet syndrome had unfavourable outcomes, whilst patients with focal epilepsy, proven to arise from a single structural lesion, had good results. We conclude that the value of epilepsy surgery in patients with an SCN1A variant rests on two issues: understanding whether the variant is pathogenic and the patient's anatomo-electroclinical phenotype. Careful evaluation of epilepsy phenotype integrated with understanding the significance of genetic variants is essential in determining a patient's suitability for epilepsy surgery. Patients with focal onset epilepsy may benefit from epilepsy surgery, whereas those with Dravet syndrome do not. WHAT THIS PAPER ADDS: Patients should not automatically be excluded from epilepsy surgery evaluation if they carry an SCN1A variant. Patients with focal epilepsy may benefit from epilepsy surgery; those with Dravet syndrome do not.

Misdiagnosis and pitfalls in Panayiotopoulos syndrome

Panayiotopoulos syndrome (PS) is a frequent (6% among children of 1-15 years) and benign epileptic syndrome, characterized by predominantly autonomic symptoms (emesis, pallor, flushing, cyanosis, mydriasis/miosis, cardiorespiratory and thermoregulatory alterations, incontinence of urine and/or feces, hypersalivation, and modifications of intestinal motility) associated with simple motor focal seizures, which can be followed by secondary generalization. Panayiotopoulos syndrome can be extremely insidious, because it can mimic several condition, such as gastroenteritis, gastroesophageal reflux disease, encephalitis, syncope, migraine, sleep disorders, or even metabolic diseases. This peculiar pleiotropism should be kept in mind by child neurologists and pediatricians and general practitioners, because a wrong diagnosis may lead to inappropriate interventions. The consequences are high morbidity, costly mismanagement, and stress for children and their parents. The availability of electroencephalography (EEG) recording in pediatric Emergency Departments might be useful for a prompt and not-cost-consuming diagnosis. On the other hand, it is important to be aware of the possible, multifaceted, clinical presentations of PS and its clinical, radiological, and neurophysiological features in order to improve both recognition and management.

Sleep Related Epilepsy and Pharmacotherapy: An Insight

In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.

SCN1A clinical spectrum includes the self-limited focal epilepsies of childhood

INTRODUCTION

Amongst autosomal dominant genetic epilepsy with febrile seizures plus (GEFS+) families, SCN1A variants are the most common genetic cause. Initially regarded as a generalized form of epilepsy, the GEFS+ spectrum is now known to include some focal epilepsies, but it is generally not conceptualized as extending to the self-limited focal epilepsies of childhood, such as Panayiotopoulos syndrome. There are, however, three reports of SCN1A variants in Panayiotopoulos syndrome. We describe the variable clinical phenotypes that include the self-limited focal epilepsies of childhood, present in a large GEFS+ family, segregating a heterozygous SCN1A missense variant.

MATERIAL AND METHODS

Electro-clinical details on all putatively affected family members were sought and blood samples were taken for genetic analysis. Two individuals were chosen for SCN1A testing. All 26 exons and exon-intron junctions were amplified, sequenced and analyzed. This was followed by pedigree segregation analysis of the variant identified.

RESULTS

A pathogenic heterozygous SCN1A (c.2624C>A; p.Thr875Lys) variant was identified. Sixteen of the 18 variant positive family members were affected (88% penetrance): 8 with febrile seizures, 2 febrile seizures plus, 1 unclassified seizures and 5 with self-limited focal epilepsy of childhood. Of these, one was diagnosed with atypical childhood epilepsy with centrotemporal spikes and four with Panayiotopoulos syndrome.

DISCUSSION

By characterizing the heterogeneous clinical phenotypes in a large, SCN1A mutation positive GEFS+ family, we conclude that the GEFS+ spectrum can extend to the self-limited focal epilepsies of childhood, including Panayiotopoulos syndrome, and in turn highlight the complex genotype-phenotype correlations associated with SCN1A-related epilepsies.

From focal epilepsy to Dravet syndrome--Heterogeneity of the phenotype due to SCN1A mutations of the p.Arg1596 amino acid residue in the Nav1.1 subunit

OBJECTIVE

The aim of this study was to analyze the intra-/interfamilial phenotypic heterogeneity due to variants at the highly evolutionary conservative p.Arg1596 residue in the Nav1.1 subunit.

MATERIALS/PARTICIPANTS

Among patients referred for analysis of the SCN1A gene one recurrent, heritable mutation was found in families enrolled into the study. Probands from those families even clinically diagnosed with atypical Dravet syndrome (DS), generalized epilepsy with febrile seizures plus (GEFS+), and focal epilepsy, had heterozygous p.Arg1596 His/Cys missense substitutions, c.4787G>T and c.4786C>T in the SCN1A gene.

METHOD

Full clinical evaluation, including cognitive development, neurological examination, EEGs, MRI was performed in probands and affected family members in developmental age. The whole SCN1A gene sequencing was performed for all probands. The exon 25, where the identified missense substitutions are localized, was directly analyzed for the other family members.

RESULTS

Mutation of the SCN1A p.1596Arg was identified in three families, in one case substitution p.Arg1596Cys and in two cases p.Arg1596His. Both mutations were previously described as pathogenic and causative for DS, GEFS+ and focal epilepsy. Spectrum of phenotypes among presented families with p.Arg1596 mutations shows heterogeneity ranged from asymptomatic cases, through FS and FS+ to GEFS+/Panayiotopoulos syndrome and epilepsies with and without febrile seizures, and epileptic encephalopathy such as DS. Phenotypes differ among patients displaying both focal and generalized epilepsies. Some patients demonstrated additionally Asperger syndrome and ataxia.

CONCLUSION

Clinical picture heterogeneity of the patients carrying mutation of the same residue indicates the involvement of the other factors influencing the SCN1A gene mutations' penetrance.

Panayiotopoulos syndrome: a case series from Turkey

The aim of the study was to evaluate the demographic, clinical, and EEG characteristics of patients with Panayiotopoulos syndrome (PS) and the course of their illness. Thirty-eight patients followed up with a diagnosis of PS between January 2011 and December 2013 were evaluated. We found high rates of personal history of febrile convulsions, breath-holding spells, and family history of febrile convulsions, afebrile convulsion/epilepsy, migraine, and breath-holding spells. Seizures started before the age of eight in 87% of the patients, and the mean age at seizure onset was 4.6 years. Seizures were sleep-related in 81.5%, and autonomic status was seen in a third of the patients. The number of seizures was between 2 and 10 in 66% of the patients. The most common symptoms were ictus emeticus, eye/head deviation, and altered consciousness. Rolandic features were seen in 26% of the patients, and visual symptoms in 5%. Multifocal epileptiform discharges on EEG were identified in 84% of the patients. Two or more antiepileptic drugs were required in only 13% of the patients. Evolution to electrical status epilepticus in sleep and Gastaut-type epilepsy were seen in patients with more than ten seizures. The high rates of febrile convulsions, afebrile convulsions/epilepsy, migraine, and breath-holding spells in the patients and families suggest the importance of genetic factors and, perhaps, a common pathogenesis. However, the high rates of febrile convulsions and breath-holding spells in patients can be related to a misdiagnosis because of the similar symptoms. Despite its disturbing symptoms, PS is a benign epileptic syndrome requiring multiple antiepileptic drug use only in a small proportion of patients.

Atypical multifocal Dravet syndrome lacks generalized seizures and may show later cognitive decline

AIM

To show that atypical multifocal Dravet syndrome is a recognizable, electroclinical syndrome associated with sodium channel gene (SCN1A) mutations that readily escapes diagnosis owing to later cognitive decline and tonic seizures.

METHOD

Eight patients underwent electroclinical characterization. SCN1A was sequenced and copy number variations sought by multiplex ligation-dependent probe amplification.

RESULTS

All patients were female (age range at assessment 5-26y) with median seizure onset at 6.5 months (range 4-19mo). The initial seizure was brief in seven and status epilepticus only occurred in one; three were febrile. Focal seizures occurred in four patients and bilateral convulsion in the other four. All patients developed multiple focal seizure types and bilateral convulsions, with seizure clusters in six. The most common focal seizure semiology (six out of eight) comprised unilateral clonic activity. Five also had focal or asymmetric tonic seizures. Rare or transient myoclonic seizures occurred in six individuals, often triggered by specific antiepileptic drugs. Developmental slowing occurred in all: six between 3 years and 8 years, and two around 1 year 6 months. Cognitive outcome varied from severe to mild intellectual disability. Multifocal epileptiform discharges were seen on electroencephalography. Seven out of eight patients had SCN1A mutations.

INTERPRETATION

Atypical, multifocal Dravet syndrome with SCN1A mutations may not be recognized because of later cognitive decline and frequent tonic seizures.

Autonomic epileptic seizures, autonomic effects of seizures, and SUDEP

Many generalized tonic-clonic seizures are accompanied by profound autonomic changes. However, autonomic seizures and autonomic status epilepticus can also be seen with specific electroclinical syndromes (Panayiotopoulos syndrome), etiologies, and localizations. Such autonomic symptoms may impact cardiorespiratory function. While it is likely that several factors contribute to SUDEP, further study of both ictal respiratory and cardiac changes and underlying neuroanatomical mechanisms involved in autonomic seizure semiology are likely to provide important data to improve our understanding of the pathophysiology of this devastating condition. This paper will review the association between autonomic symptoms and epileptic seizures and will highlight the work of three young investigators. Drs. Lisa Bateman and Brian Moseley will review their work on cardiorespiratory effects of recorded seizures and how this assists in our understanding of SUDEP. Dr. John Millichap will review autonomic seizures and autonomic dysfunctions related to childhood epilepsy and will discuss the importance of expanded research efforts in this field.

Idiopathic focal epilepsies

In this chapter we include a series of epilepsies with onset in pediatric age characterized by focal seizures, idiopathic etiology, normal psychomotor development, and a benign course related to the spontaneous remission of seizures without sequelae. These entities are age-dependent and seizures tend to disappear spontaneously. For these reasons often the drug treatment is not necessary. On the basis of genetic assessment idiopathic focal epilepsies can be divided into two groups: nonautosomal dominant and autosomal dominant. In the group of nonautosomal entities we include benign epilepsy with centro-temporal spikes, Panayiotopoulos syndrome, idiopathic childhood occipital epilepsy described by Gastaut, and benign idiopathic midline spikes epilepsy. Seizures are rare, sometimes prolonged, as autonomic status in Panayiotopoulos syndrome. A common feature is the presence of peculiar EEG interictal paroxysmal abnormalities. In the group with an autosomal dominant mode of inheritance we include benign familial infantile seizures and benign familial neonatal-infantile seizures. These entities are characterized by partial seizures in cluster, self-limited in a brief period during the first months of life. There are no typical interictal EEG abnormalities. In some families a mutation in SCN2A, the gene coding for the 2α subunit of the voltage-gated sodium channel, has been described.

Fever and fever-related epilepsies

Febrile seizures are a common emergency faced by general pediatricians. They are mostly self-limiting, isolated events with no sequelae in later life. A minority are more complex. In the acute stage, there are a small number of underlying etiologies that are important to recognize in order to determine the prognosis accurately and to optimize management. There has been a long-standing debate about the relationship of early febrile seizures to the later development of epilepsy. It is now clear that this risk differs for simple and complex febrile seizures: complex febrile seizures may herald the presentation of a number of epilepsy syndromes of which febrile and illness-related seizures are part of the phenotype. This review examines the existing knowledge on febrile seizures and the various clinical phenotypes to which they are linked.

Sodium channels and the neurobiology of epilepsy

Voltage-gated sodium channels (VGSCs) are integral membrane proteins. They are essential for normal neurologic function and are, currently, the most common recognized cause of genetic epilepsy. This review summarizes the neurobiology of VGSCs, their association with different epilepsy syndromes, and the ways in which we can experimentally interrogate their function. The most important sodium channel subunit of relevance to epilepsy is SCN1A, in which over 650 genetic variants have been discovered. SCN1A mutations are associated with a variety of epilepsy syndromes; the more severe syndromes are associated with truncation or complete loss of function of the protein. SCN2A is another important subtype associated with epilepsy syndromes, across a range of severe and less severe epilepsies. This subtype is localized primarily to excitatory neurons, and mutations have a range of functional effects on the channel. SCN8A is the other main adult subtype found in the brain and has recently emerged as an epilepsy gene, with the first human mutation discovered in a severe epilepsy syndrome. Mutations in the accessory β subunits, thought to modulate trafficking and function of the α subunits, have also been associated with epilepsy. Genome sequencing is continuing to become more affordable, and as such, the amount of incoming genetic data is continuing to increase. Current experimental approaches have struggled to keep pace with functional analysis of these mutations, and it has proved difficult to build associations between disease severity and the precise effect on channel function. These mutations have been interrogated with a range of experimental approaches, from in vitro, in vivo, to in silico. In vitro techniques will prove useful to scan mutations on a larger scale, particularly with the advance of high-throughput automated patch-clamp techniques. In vivo models enable investigation of mutation in the context of whole brains with connected networks and more closely model the human condition. In silico models can help us incorporate the impact of multiple genetic factors and investigate epistatic interactions and beyond.

Na+ channelopathies and epilepsy: recent advances and new perspectives

Mutations of ion channel genes have a major role in the pathogenesis of several epilepsies, confirming that some epilepsies are disorders due to the impairment of ion channel function (channelopathies). Voltage-gated Na(+) channels (VGSCs) play an essential role in neuronal excitability; it is, therefore, not surprising that most mutations associated with epilepsy have been identified in genes coding for VGSCs subunits. Epilepsies linked to VGSCs mutations range in severity from mild disorders, such as benign neonatal-infantile familial seizures and febrile seizures, to severe and drug-resistant epileptic encephalopathies. SCN1A is the most clinically relevant of all of the known epilepsy genes, several hundred mutations have been identified in this gene. This review will summarize recent advances and new perspectives on Na(+) channels and epilepsy. A better understanding of the genetic basis and of how gene defects cause seizures is mandatory to direct future research for newer selective and more efficacious treatments.

"Electro-clinical syndromes" with onset in paediatric age: the highlights of the clinical-EEG, genetic and therapeutic advances

The genetic causes underlying epilepsy remain largely unknown, and the impact of available genetic data on the nosology of epilepsy is still limited. Thus, at present, classification of epileptic disorders should be mainly based on electroclinical features. Electro-clinical syndrome is a term used to identify a group of clinical entities showing a cluster of electro-clinical characteristics, with signs and symptoms that together define a distinctive, recognizable, clinical disorder. These often become the focus of treatment trials as well as of genetic, neuropsychological, and neuroimaging investigations. They are distinctive disorders identifiable on the basis of a typical age onset, specific EEG characteristics, seizure types, and often other features which, when taken together, permit a specific diagnosis which, in turn, often has implications for treatment, management, and prognosis. Each electro-clinical syndrome can be classified according to age at onset, cognitive and developmental antecedents and consequences, motor and sensory examinations, EEG features, provoking or triggering factors, and patterns of seizure occurrence with respect to sleep. Therefore, according to the age at onset, here we review the more frequently observed paediatric electro-clinical syndrome from their clinical-EEG, genetic and therapeutic point of views.

Mosaic SCN1A mutations in familial partial epilepsy with antecedent febrile seizures

SCN1A is the most relevant epilepsy gene. Mutations of SCN1A generate phenotypes ranging from the extremely severe form of Dravet syndrome (DS) to a mild form of generalized epilepsy with febrile seizures plus (GEFS+). Mosaic SCN1A mutations have been identified in rare familial DS. It is suspected that mosaic mutations of SCN1A may cause other types of familial epilepsies with febrile seizures (FS), which are more common clinically. Thus, we screened SCN1A mutations in 13 families with partial epilepsy with antecedent febrile seizures (PEFS+) using denaturing high-performance liquid chromatography and sequencing. The level of mosaicism was further quantified by pyrosequencing. Two missense SCN1A mutations with mosaic origin were identified in two unrelated families, accounting for 15.4% (2/13) of the PEFS+ families tested. One of the mosaic carriers with ~25.0% mutation of c.5768A>G/p.Q1923R had experienced simple FS; another with ~12.5% mutation of c.4847T>C/p.I1616T was asymptomatic. Their heterozygous children had PEFS+. Recurrent transmission occurred in both families, as noted in most of the families with germline mosaicism reported previously. The two mosaic mutations identified in this study are less destructive missense, compared with the more destructive truncating and splice-site mutations identified in the majority of previous studies. This is the first report of mosaic SCN1A mutations in families with probands that do not exhibit DS, but manifest only a milder phenotype. Therefore, such families with mild cases should be approached with caution in genetic counseling and the possibility of mosaicism origin associated with high recurrence risk should be excluded.

Fever as a seizure precipitant factor in Panayiotopoulos syndrome: a clinical and genetic study

PURPOSE

To examine fever as a precipitating factor for focal seizures in patients with Panayiotopoulos syndrome (PS) and evaluate the role of SCN1A in PS patients with seizures triggered by fever.

METHODS

From January 2000 to June 2008, we identified patients referred for seizures who fulfilled the criteria of PS. Patients were divided into two groups, according to the presence (group A) or the absence (group B) of seizures triggered by fever. Electroclinical features of the two groups were compared. In addition, an analysis of SCN1A in patients of group A was performed.

RESULTS

Thirty patients fulfilled the inclusion criteria. Eleven patients (36%) had at least one focal autonomic seizure triggered by fever (group A). In group A, 7/11 patients (63.5%) had the first focal autonomic seizure during a febrile illness. Two of these 7 patients were misdiagnosed at the onset of PS. The median age at the onset of PS was slightly lower in group A than in group B (p=.050). Moreover, patients in group A more frequently had a positive familial history of febrile seizures (FS) (p=.047). No mutations of SCN1A were found in any of the 10 patients screened.

CONCLUSION

Fever is a common trigger for focal autonomic seizures in PS. Knowing that an autonomic manifestation during fever can be an epileptic seizure could facilitate diagnosis and prevent unnecessary investigations and erroneous treatments. Moreover, our data show that SCN1A gene does not contribute significantly to susceptibility to autonomic seizures during fever in patients with PS.

Cardiovascular and neuroendocrine features of Panayiotopoulos syndrome in three siblings

OBJECTIVE

Panayiotopoulos syndrome is a benign idiopathic childhood epilepsy characterized by altered autonomic activity at seizure onset.

METHODS

Three siblings with Panayiotopoulos syndrome underwent 24-hour EEG recording and head-up tilt testing with continuous blood pressure and RR interval monitoring. Plasma catecholamines and vasopressin were measured while supine, upright, and during a typical seizure.

RESULTS

Patient 1, a 12-year-old girl, had a history of involuntary lacrimation, abdominal pain, and recurrent episodes of loss of muscle tone and unresponsiveness followed by somnolence. Her EEG revealed bilateral frontotemporal spikes. Patient 2, a 10-year-old boy, had episodic headaches with pinpoint pupils, skin flushing of the face, trunk, and extremities, purple discoloration of hands and feet, diaphoresis, nausea, and vomiting. Tilt testing triggered a typical seizure after 9 minutes; there was a small increase in blood pressure (+5/4 mm Hg, systolic/diastolic) and pronounced increases in heart rate (+59 bpm) and norepinephrine (+242 pg/mL), epinephrine (+175 pg/mL), and vasopressin (+22.1 pg/mL) plasma concentrations. Serum glucose was elevated (206 mg/dL). His EEG revealed right temporal and parietal spikes. Patient 3, an 8-year-old boy, had a history of restless legs at night, enuresis, night terrors, visual hallucinations, cyclic abdominal pain, and nausea. His EEG showed bitemporal spikes.

CONCLUSION

Hypertension, tachycardia, and the release of vasopressin suggest activation of the central autonomic network during seizures in familial Panayiotopoulos syndrome. These autonomic and neuroendocrine features may be useful in the diagnosis and may have therapeutic implications.

Dravet syndrome as epileptic encephalopathy: evidence from long-term course and neuropathology

Dravet syndrome is an epilepsy syndrome of infantile onset, frequently caused by SCN1A mutations or deletions. Its prevalence, long-term evolution in adults and neuropathology are not well known. We identified a series of 22 adult patients, including three adult post-mortem cases with Dravet syndrome. For all patients, we reviewed the clinical history, seizure types and frequency, antiepileptic drugs, cognitive, social and functional outcome and results of investigations. A systematic neuropathology study was performed, with post-mortem material from three adult cases with Dravet syndrome, in comparison with controls and a range of relevant paediatric tissue. Twenty-two adults with Dravet syndrome, 10 female, were included, median age 39 years (range 20-66). SCN1A structural variation was found in 60% of the adult Dravet patients tested, including one post-mortem case with DNA extracted from brain tissue. Novel mutations were described for 11 adult patients; one patient had three SCN1A mutations. Features of Dravet syndrome in adulthood include multiple seizure types despite polytherapy, and age-dependent evolution in seizure semiology and electroencephalographic pattern. Fever sensitivity persisted through adulthood in 11 cases. Neurological decline occurred in adulthood with cognitive and motor deterioration. Dysphagia may develop in or after the fourth decade of life, leading to significant morbidity, or death. The correct diagnosis at an older age made an impact at several levels. Treatment changes improved seizure control even after years of drug resistance in all three cases with sufficient follow-up after drug changes were instituted; better control led to significant improvement in cognitive performance and quality of life in adulthood in two cases. There was no histopathological hallmark feature of Dravet syndrome in this series. Strikingly, there was remarkable preservation of neurons and interneurons in the neocortex and hippocampi of Dravet adult post-mortem cases. Our study provides evidence that Dravet syndrome is at least in part an epileptic encephalopathy.

Panayiotopoulos syndrome: probable genetic origin, but not in SCN1A

Panayiotopoulos syndrome is encompassed in the classification of the ILAE in idiopathic focal epilepsies. Mutations in the SCN1A gene have been associated with the development of this syndrome. We present two cases of Panayiotopoulos syndrome in two monozygotic twins, who underwent a molecular analysis of SCN1A, but no alteration was found. These cases suggest a genetic origin, and SCN1A appears to be associated with the outcome but not with the development of this syndrome.

Etiological heterogeneity in autism spectrum disorders: more than 100 genetic and genomic disorders and still counting

There is increasing evidence that autism spectrum disorders (ASDs) can arise from rare highly penetrant mutations and genomic imbalances. The rare nature of these variants, and the often differing orbits of clinical and research geneticists, can make it difficult to fully appreciate the extent to which we have made progress in understanding the genetic etiology of autism. In fact, there is a persistent view in the autism research community that there are only a modest number of autism loci known. We carried out an exhaustive review of the clinical genetics and research genetics literature in an attempt to collate all genes and recurrent genomic imbalances that have been implicated in the etiology of ASD. We provide data on 103 disease genes and 44 genomic loci reported in subjects with ASD or autistic behavior. These genes and loci have all been causally implicated in intellectual disability, indicating that these two neurodevelopmental disorders share common genetic bases. A genetic overlap between ASD and epilepsy is also apparent in many cases. Taken together, these findings clearly show that autism is not a single clinical entity but a behavioral manifestation of tens or perhaps hundreds of genetic and genomic disorders. Increased recognition of the etiological heterogeneity of ASD will greatly expand the number of target genes for neurobiological investigations and thereby provide additional avenues for the development of pathway-based pharmacotherapy. Finally, the data provide strong support for high-resolution DNA microarrays as well as whole-exome and whole-genome sequencing as critical approaches for identifying the genetic causes of ASDs.

Status epilepticus in fragile X syndrome

Epilepsy is frequent in fragile X syndrome (FXS), the most common cause of inherited mental retardation. Status epilepticus (SE), however, seems exceptional in FXS, particularly as an initial epileptic manifestation. To our knowledge, SE was reported in only four FXS patients. We report the clinical features and electroencephalography (EEG) findings of five children with FXS, who presented with SE as their initial seizure.

Panayiotopoulos syndrome: a clinical, EEG, and neuropsychological study of 93 consecutive patients

PURPOSE

To explore the clinical, electroencephalography (EEG), neuropsychological features, and prognosis of Panayiotopoulos syndrome (PS).

METHODS

Of 1,794 children aged between 1 and 14 years referred for the first afebrile focal seizure, between January 1992 and December 2004, 93 (5.2%) had PS according to clinical criteria.

RESULTS

Age at onset ranged from 1.1 to 8.6 years, and was earlier in children with more than one seizure. Autonomic seizures followed a stereotypical onset and progression. Emesis, pallor, or flushing was almost always among the first symptoms that usually culminated in vomiting (77.4% of patients). More than half (55%) of seizures were longer than 30 min but these did not appear to affect remission and number of seizures. Interictal EEG showed great variability, with 79.5% of patients showing spikes of variable localizations and evolution over time; 16.1% had background abnormalities only, and 5.4% had consistently normal EEG studies. Onsets in five ictal EEGs were posterior or anterior-left or right. On neuropsychological testing, IQ and subtests of Wechsler Intelligence Scale for Children-Revised (WISC-R) were within normal limits, although some minor statistically significant differences were found in arithmetic, comprehension, and picture arrangement in comparison with controls. Cumulative probability of recurrence was 57.6%, 45.6%, 35.1%, and 11.7% at 6, 12, 24, and 36 months, respectively, after the first seizure. Thirty-four (58.6%) of 59 patients treated with antiepileptic drugs continued having seizures before ultimate remission.

DISCUSSION

PS is a uniform childhood susceptibility to autonomic seizures that is related to early age of development and with excellent prognosis with regard to seizure remission and neuropsychological development.