Hsp90aa1/JUN/Ccl2 regulatory axis mediates migration and differentiation of NSPCs, promoting the onset and progression of early post-ischemic stroke epilepsy.

Early-onset epilepsy following ischemic stroke is a severe neurological condition, the pathogenesis of which remains incompletely understood. Recent studies suggest that Neural stem/progenitor cells (NSPCs) play a crucial role in the disease process, yet the precise molecular mechanisms regulating NSPCs have not been thoroughly investigated. This study utilized single-cell transcriptome sequencing and bioinformatics analysis to identify disease-related genes, which were subsequently validated in both in vitro and in vivo experiments. The findings revealed that Hsp90aa1 (heat shock protein 90 kDa alpha, class A member 1), Jun proto-oncogene (JUN), and CC Motif Ligation 2 (Ccl2) constitute an important regulatory axis influencing the migration and differentiation of NSPCs, potentially impacting the onset and progression of early-onset epilepsy post-ischemic stroke. Additionally, the expression of Hsp90aa1 was found to influence the likelihood of seizure occurrence and the severity of brain ischemia.

Gamma-Tubulin 1 (TUBG1) Mutation-Associated Lissencephaly and Microcephaly in an Indian Child: A Rare Case.

Malformations of cortical development (MCD) are a group of disorders affecting the normal development of the human cortex and are significant causes of delay in psychomotor development and epilepsy in children. Lissencephaly (smooth brain) forms a major group of brain malformations. Microtubules help in the migration of neuronal cells. Defect in tubulin gene alpha-tubulin (TUBA), beta-tubulin (TUBB), and gamma-tubulin (TUBG) leads to defective neuronal migration. This group of disorders is termed as "tubulinopathies." The important genes implicated in causing lissencephaly are LIS1, XLIS, and TUBA1A gene. Recently, a mutation in the TUBG1 gene is associated with it. Here, we report a one-and-a-half-year-old girl with global developmental delay, microcephaly, infantile-onset epilepsy, epileptic spasms, dysmorphism, and motor signs. There was no significant birth history. Neuroimaging (MRI) showed a broad thick gyri and a decreased number of sulci suggestive of lissencephaly/pachygyria spectrum. There was dilatation of the ventricles, and no grey matter heterotopia was noted. Sleep EEG showed multifocal epileptiform discharges. The child was treated with multiple anti-seizure medicines (ASMs). A genetic test, whole exome sequencing, was done to determine the etiology of MCD. A heterozygous missense variation in exon 6 of the TUBG1 gene was identified and reported as a "variant of unknown significance." Still, because the genotype matched with the clinical phenotype of the patient, it was considered clinically significant. Therefore, a complete diagnosis of TUBG1 mutation-associated cortical malformation (lissencephaly/pachygyria) with microcephaly and early-onset epilepsy was established. TUBG1 mutation is de novo in most cases, but parental testing is recommended. The parents of such patients need to be counseled about the need for prenatal testing and the risk of the disease to siblings. The overall prognosis in such cases is poor because of refractory seizures, physical limitations, and intellectual disability.

Whole-Genome Sequencing Among Kazakhstani Children with Early-Onset Epilepsy Revealed New Gene Variants and Phenotypic Variability.

In Kazakhstan, there is insufficient data on genetic epilepsy, which has its own clinical and management implications. Thus, this study aimed to use whole genome sequencing to identify and evaluate genetic variants and genetic structure of early onset epilepsy in the Kazakhstani pediatric population. In this study, for the first time in Kazakhstan, whole genome sequencing was carried out among epilepsy diagnosed children. The study involved 20 pediatric patients with early onset epilepsy and no established cause of the disease during the July-December, 2021. The average age at enrolment was 34.5 months, with a mean age at seizure onset of 6 months. Six patients (30%) were male, and 7 were familial cases. We identified pathogenic and likely pathogenic variants in 14 (70%) cases, among them, 6 novel disease gene variants (KCNQ2, CASK, WWOX, MT-CO3, GRIN2D, and SLC12A5). Other genes associated with the disease were SCN1A (x2), SLC2A1, ARX, CACNA1B, PCDH19, KCNT1, and CHRNA2. Identification of the genetic causes in 70% of cases confirms the general structure of the etiology of early onset epilepsy and the necessity of using NGS in diagnostics. Moreover, the study describes new genotype-phenotypic correlations in genetic epilepsy. Despite certain limitations of the study, it can be concluded that the genetic etiology of pediatric epilepsy in Kazakhstan is very broad and requires further research.

A de novo missense variant in GABRA4 alters receptor function in an epileptic and neurodevelopmental phenotype.

Variants in γ-aminobutyric acid A (GABAA ) receptor genes cause different forms of epilepsy and neurodevelopmental disorders. To date, GABRA4, encoding the α4-subunit, has not been associated with a monogenic condition. However, preclinical evidence points toward seizure susceptibility. Here, we report a de novo missense variant in GABRA4 (c.899C>T, p.Thr300Ile) in an individual with early-onset drug-resistant epilepsy and neurodevelopmental abnormalities. An electrophysiological characterization of the variant, which is located in the pore-forming domain, shows accelerated desensitization and a lack of seizure-protective neurosteroid function. In conclusion, our findings strongly suggest an association between de novo variation in GABRA4 and a neurodevelopmental disorder with epilepsy.

Trio exome sequencing identified a novel de novo WASF1 missense variant leading to recurrent site substitution in a Chinese patient with developmental delay, microcephaly, and early-onset seizures: A mutational hotspot p.Trp161 and literature review.

BACKGROUND: Neurodevelopmental disorder with absent language and variable seizures (NEDALVS, OMIM # 618707) is a newly described autosomal dominant condition caused by heterozygous de novo mutation in WASF1 gene. WASF1 is a key component of the WAVE regulatory complex (WRC) required for actin polymerization. So far, only 3 distinct truncating variants clustering at the WCA domain, 3 missense variants localized to the meander region and a copy number variant (CNV) of WASF1 have been identified among 11 NEDALVS cases previously reported. CASE REPORT: We report a pediatric patient carrying novel de novo heterozygous missense variant (NM_003931.2: c.481T > C, p.Trp161Arg) in WASF1 gene. During the first hospitalization at age of 5.5 months, the patient was initially diagnosed with infantile spasms, developmental delay (DD) and microcephaly due to nodding-like epileptic spasms in clusters and hypsarrhythmia on video-electroencephalography, lacking head control and body rollover, and abnormal head circumference 39 cm (<-2SD). The genetic diagnosis with a causal WASF1 variant detected by trio exome sequencing indicated the rare NEDALVS. LITERATURE REVIEW: All the reported NEDALVS cases published in the PubMed English literature were reviewed to summarize the genetic and phenotypic spectrum of this novel disorder. CONCLUSION: We describe the third patient with a recurrently mutated amino acid site at p.Trp161 in WASF1, currently the 12th patient with NEDALVS. This hotspot missense variant and the truncating variants in WASF1 lead to similar phenotypic patterns with core features of severe DD/ID, and seizures, hypotonia, and microcephaly frequently observed. Our finding expands the WASF1 mutation spectrum and confirms the de novo hotspot missense variant at p.Trp161, further supporting the association of the novel NEDALVS with WASF1 gene and the actin regulatory pathway.

Epilepsy Syndromes in the First Year of Life and Usefulness of Genetic Testing for Precision Therapy.

The high pace of gene discovery has resulted in thrilling advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, or genomes are now increasingly available and have led to a significant higher diagnostic yield in early-onset epilepsies and enabled precision medicine approaches. These have been instrumental in providing insights into the pathophysiology of both early-onset benign and self-limited syndromes and devastating developmental and epileptic encephalopathies (DEEs). Genetic heterogeneity is seen in many epilepsy syndromes such as West syndrome and epilepsy of infancy with migrating focal seizures (EIMFS), indicating that two or more genetic loci produce the same or similar phenotypes. At the same time, some genes such as SCN2A can be associated with a wide range of epilepsy syndromes ranging from self-limited familial neonatal epilepsy at the mild end to Ohtahara syndrome, EIFMS, West syndrome, Lennox-Gastaut syndrome, or unclassifiable DEEs at the severe end of the spectrum. The aim of this study was to review the clinical and genetic heterogeneity associated with epilepsy syndromes starting in the first year of life including: Self-limited familial neonatal, neonatal-infantile or infantile epilepsies, genetic epilepsy with febrile seizures plus spectrum, myoclonic epilepsy in infancy, Ohtahara syndrome, early myoclonic encephalopathy, West syndrome, Dravet syndrome, EIMFS, and unclassifiable DEEs. We also elaborate on the advantages and pitfalls of genetic testing in such conditions. Finally, we describe how a genetic diagnosis can potentially enable precision therapy in monogenic epilepsies and emphasize that early genetic testing is a cornerstone for such therapeutic strategies.

A founder mutation in the PLPBP gene in families from Saguenay-Lac-St-Jean region affected by a pyridoxine-dependent epilepsy.

Pyridoxine-dependent epilepsy (PDE) is a relatively rare subgroup of epileptic disorders. They generally present in infancy as an early onset epileptic encephalopathy or seizures, refractory to standard treatments, with rapid and variable responses to vitamin B6 treatment. Whole exome sequencing of three unrelated families identified homozygous pathogenic mutation c.370_373del, p.Asp124fs in PLPBP gene in five persons. Haplotype analysis showed a single shared profile for the affected persons and their parents, leading to a hypothesis about founder effect of the mutation in Saguenay-Lac-St-Jean region of French Canadians. All affected probands also shared one single mitochondrial haplotype T2b3 and two rare variations in the mitochondrial genome m.801A>G and m.5166A>G suggesting that a single individual female introduced PLPBP mutation c.370_373del, p.Asp124fs in Quebec. The mutation p.Asp124fs causes a severe disease phenotype with delayed myelination and cortical/subcortical brain atrophy. The most noteworthy radiological finding in this Quebec founder mutation is the presence of the temporal cysts that can be used as a marker of the disease. Also, both patients, who are alive, had a history of prenatal supplements taken by their mothers as antiemetic medication with high doses of pyridoxine. In the context of suspected PDE in patients with neonatal refractory seizures, treatment with pyridoxine and/or Pyridoxal-5-phophate has to be started immediately and continued until the results of genetic analysis received. Even with early appropriate treatment, neurological outcome of our patient is still poor.

The information needs of parents of children with early-onset epilepsy: A systematic review.

OBJECTIVE: Early-onset epilepsy has broad physical and psychosocial impacts, and parents have a wide variety of information needs. This systematic review set out to assess 1) whether parents of children with early-onset epilepsy have unmet information needs and 2) their preferences regarding information content and style of information delivery. METHODS: We searched Medline, Embase, PsychInfo, and CINAHL using keywords relating to information needs, information resources, and preferences for information delivery. We limited the search to parent populations and included all peer-reviewed publications published in English after the year 2005. RESULTS: Eleven studies met our inclusion criteria. Parents reported a clear need for understandable, realistic, and focused information, highlighting a particular need for content about comorbidities and emotional support. Parents reported limited availability of detailed information resources on early-onset epilepsy, which compromised their ability to access appropriate healthcare services. Unmet information needs were associated with greater levels of stress, poorer psychosocial outcomes, and lower satisfaction with healthcare services. SIGNIFICANCE: The results highlight the importance of detailed epilepsy information for families. Healthcare professionals should be aware of the impact of a lack of epilepsy information on family wellbeing. Multipronged and tailored interventions targeting the information needs of families are warranted.

Determining the best candidates for next-generation sequencing-based gene panel for evaluation of early-onset epilepsy.

BACKGROUND: Genetic testing is an emerging diagnostic approach in early-onset epilepsy. Identification of the heterogeneous genetic causes of epilepsy may mitigate unnecessary evaluations and allow more accurate diagnosis and therapy. We aimed to uncover genetic causes of early-onset epilepsy using next-generation sequencing (NGS) to elucidate the diagnostic candidates and evaluate the diagnostic yield of targeted gene panel testing. METHODS: We evaluated 116 patients with early-onset epilepsy developed before 2 years old and normal brain imaging using a NGS-based targeted gene panel. Variants were classified according to their pathogenicity, and the diagnostic yield of the targeted genes and associated clinical factors were determined. RESULTS: We detected 40 disease-causing variants with diagnostic yield of 34.5% (19 pathogenic, 21 likely pathogenic). Twelve variants were novel. The most commonly detected genes were SCN1A, associated with Dravet syndrome, and PRRT2, associated with benign familial infantile epilepsy. Other variants were identified in ARX, SCN2A, KCNQ2, PCDH19, STXBP1, DEPDC5, and SCN8A. The age of seizure onset and family history were associated with disease-causing variants. CONCLUSION: Next-generation sequencing-based targeted testing is an effective diagnostic test, with 30%-40% comparable diagnostic yield. Patients with earlier seizure onset and family history of epilepsy were the best candidates for testing. For pediatric patients with early-onset epilepsy, genetic diagnosis is important for accurate prognosis and treatment.

Early-onset epileptic encephalopathy related to germline PIGA mutations: A series of 5 cases.

The molecular diagnosis of early-onset epileptic encephalopathy (EOEE), an expanding field in child neurology, is becoming increasingly possible thanks to the widespread availability of next-generation sequencing and whole-exome sequencing. In the past 15 years, mutations in STXBP1, KCNQ2, SCN2A, SCN8A and numerous other genes have been reported, giving a more accurate insight for these rare diseases. Among these genes, germline mutations in Phosphatidyl Inositol Glycan A (PIGA) gene were first reported in 2012. Located on Xp22.2, PIGA is involved in the synthesis of GPI (glycosylphosphatidylinositol) which acts as a membrane anchor for different proteins: enzymes, adhesion molecules, regulation of the complement way, and co-receptor in transduction signal. Children suffering from this condition exhibit developmental delay with early-onset epilepsy, severe dysmorphic signs, multi-visceral anomalies and early death in the most severe forms. Here, we report five cases of germline PIGA mutations, with two missense mutations that have not been reported to date. We provide a new insight into the electroclinical phenotype. At the onset, epileptic spasms and focal-onset seizures with upper limbs and ocular involvements were present. Epilepsy proved pharmacoresistant in 4 out of 5 cases. Interictal EEG may be normal at the onset of epilepsy, but abnormalities in electroencephalographic studies were eventually present in all cases. Different types of seizures may be present simultaneously, and epileptic phenotypes evolve with aging.

Electroclinical Findings of SYNJ1 Epileptic Encephalopathy.

INTRODUCTION: Early-onset epileptic encephalopathies are among the most severe early-onset epilepsies, leading to progressive neurodegeneration. An increasing number of novel genetic causes continue to be uncovered as the primary etiology. RESULTS: We report a girl infant of Semitic (Saudi Arabian) descent who presented with multifocal seizures and later developed intractable infantile spasms and myoclonic seizures. Her clinical features and electroencephalography were consistent with early-onset epileptic encephalopathy. Whole exome sequence analysis showed homozygous novel pathogenic variant (variant p.Q287PfsX27; coding DNA c.858_862delACAAA) in the SYNJ1 gene. CONCLUSION: This is a newly described early-onset epileptic encephalopathy secondary to a critical reduction of the dual phosphatase activity of SYNJ. Clinical features include early-onset intractable focal, myoclonic seizures, infantile spasms, and hypotonia progressing to spastic quadriparesis, opisthotonus, dystonia, profound developmental delay, and a progressive neurodegenerative course. Brain magnetic resonance imaging is usually normal. Electroencephalography shows diffuse slowing with multifocal epileptiform discharges or modified hypsarrhythmia. These findings further expand the clinical spectrum of synaptic dysregulation in patients with severe epilepsy and emphasize the importance of this biological pathway in seizure pathophysiology.

Identification of PCDH19 Gene Mutations/Deletions in Patients with Early Onset Epilepsy.

BACKGROUND AND AIMS: PCDH19 gene, which encodes protocadherin 19, is associated with epilepsy and intellectual disability, mainly in affected females. The clinical manifestations are heterogeneous and the main features include early onset seizure, generalized or focal seizures sensitive to fever, and brief seizures occurring in clusters. The disorders exhibit a unique and unusual X-linked pattern of expression. We aimed to investigate PCDH19 mutations/deletions in patients with epilepsy and describe the clinical/molecular features. METHODS: PCDH19 gene was analyzed in 35 Turkish female patients from 34 families with early-onset epilepsy via direct sequencing and multiplex ligation-dependent probe amplification analysis. Additionally, array comparative genomic hybridization analysis was performed in patients with whole gene deletion. RESULTS: We identified 2 different heterozygous mutations in 2 unrelated probands (5. 7%) which were located in exon 1. Additionally, whole gene deletions were detected in dizygotic twin girls (5. 7%), who had distinct clinical features and the deletion was inherited from the unaffected father. The second twin suffered more severe clinical manifestations including autistic features, behavioral problems, mild-moderate mental retardation and seizures, which were under control with multidrug regimen when compared with the first twin. CONCLUSION: PCDH19 is a major causative gene in patients with epilepsy and further data is required to gain a better understanding of phenotype-genotype correlation. In addition to gene sequencing, deletion/duplication analysis will improve the molecular diagnosis in patients with clinical findings.

Three novel patients with epileptic encephalopathy due to biallelic mutations in the PLCB1 gene.

Biallelic mutations in the PLCB1 gene, encoding for a phospholipase C beta isoform strongly expressed in the brain, have been reported to cause infantile epileptic encephalopathy in only four children to date. We report here three additional patients to delineate the phenotypic and genotypic characteristics of the disease. Our three patients were one sporadic case with an intragenic homozygous deletion and two cousins with the homozygous p.(Arg222*) nonsense variant in PLCB1. These patients had severe to profound intellectual disability, epileptic spasms at age 3-5 months concomitant with developmental arrest or regression, other seizure types and drug-resistant epilepsy. With this report, we expand the clinical, radiologic and electroencephalographic knowledge about the extremely rare PLCB1-related encephalopathy. Since the first report in 2010, the overall number of reported patients with our additional patients is currently limited to seven. All seven patients had epileptic encephalopathy, mainly infantile spasms and 6/7 had profound intellectual disability, with one only being able to walk. Truncal hypotonia was the most frequent neurological sign, sometimes associated with pyramidal and/or extrapyramidal hypertonia of limbs. Microcephaly was inconstant. In conclusion, the phenotypical spectrum of PLCB1-related encephalopathy is relatively narrow, comprises infantile spasms and severe to profound intellectual disability, and does not seem to define a recognizable clinical entity.

Why we urgently need improved seizure and epilepsy therapies for children and neonates.

In contrast to epilepsy in adolescents and adults, neonatal seizures and early onset epilepsy poses unique challenges with significant repercussion for treatment choices. Most importantly, high seizure burden and epileptic encephalopathy are associated with developmental, behavioural and cognitive problems. The causes are multifactorial and include etiology, seizure burden, epileptic encephalopathy, but also antiseizure medication. In contrast to adults and older children only very few drugs have been licenced for infants and neonates, and after a long delay. Very recently, extrapolation of adult data has become possible as a path to speed up drug development for younger children but this is not necessarily possible for infants and neonates. With the advances in understanding the molecular basis of many epilepsies, targeted therapies become available, for example for KCNQ2 mutation related epilepsies, Dravet syndrome or tuberous sclerosis complex. Drug trials in neonates are particularly challenging because of their inconspicuous clinical presentation, the need for continuous EEG monitoring, high co-morbidity, and poor response to antiepileptic drugs. There is an urgent need for development of new drugs, evaluation of safety and efficacy of current antiseizure drugs, as well as for national policies and guidelines for the management of seizures and epilepsy in neonates and infants. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

De Novo and Inherited SETD1A Variants in Early-onset Epilepsy.

Early-onset epilepsy is a neurological abnormality in childhood, and it is especially common in the first 2 years after birth. Seizures in early life mostly result from structural or metabolic disorders in the brain, and the genetic causes of idiopathic seizures have been extensively investigated. In this study, we identified four missense mutations in the SETD1A gene (SET domain-containing 1A, histone lysine methyltransferase): three de novo mutations in three individuals and one inherited mutation in a four-generation family. Whole-exome sequencing indicated that all four of these mutations were responsible for the seizures. Mutations of SETD1A have been implicated in schizophrenia and developmental disorders, so we examined the role of the four mutations (R913C, Q269R, G1369R, and R1392H) in neural development. We found that their expression in mouse primary cortical neurons affected excitatory synapse development. Moreover, expression of the R913C mutation also affected the migration of cortical neurons in the mouse brain. We further identified two common genes (Neurl4 and Usp39) affected by mutations of SETD1A. These results suggested that the mutations of SETD1A play a fundamental role in abnormal synaptic function and the development of neurons, so they may be pathogenic factors for neurodevelopmental disorders.

Diagnostic Yield and Treatment Impact of Targeted Exome Sequencing in Early-Onset Epilepsy.

Targeted whole-exome sequencing (WES) is a powerful diagnostic tool for a broad spectrum of heterogeneous neurological disorders. Here, we aim to examine the impact on diagnosis, treatment and cost with early use of targeted WES in early-onset epilepsy. WES was performed on 180 patients with early-onset epilepsy (≤5 years) of unknown cause. Patients were classified as Retrospective (epilepsy diagnosis >6 months) or Prospective (epilepsy diagnosis <6 months). WES was performed on an Ion Proton™ and variant reporting was restricted to the sequences of 620 known epilepsy genes. Diagnostic yield and time to diagnosis were calculated. An analysis of cost and impact on treatment was also performed. A molecular diagnoses (pathogenic/likely pathogenic variants) was achieved in 59/180 patients (33%). Clinical management changed following WES findings in 23 of 59 diagnosed patients (39%) or 13% of all patients. A possible diagnosis was identified in 21 additional patients (12%) for whom supporting evidence is pending. Time from epilepsy onset to a genetic diagnosis was faster when WES was performed early in the diagnostic process (mean: 145 days Prospective vs. 2,882 days Retrospective). Costs of prior negative tests averaged $8,344 per patient in the Retrospective group, suggesting savings of $5,110 per patient using WES. These results highlight the diagnostic yield, clinical utility and potential cost-effectiveness of using targeted WES early in the diagnostic workup of patients with unexplained early-onset epilepsy. The costs and clinical benefits are likely to continue to improve. Advances in precision medicine and further studies regarding impact on long-term clinical outcome will be important.

Interaction among GRIK2 gene on epilepsy susceptibility in Chinese children.

AIMS: The association of single nucleotide polymorphisms (SNPs) of glutamate receptor 2 (GRIK2) gene, as well as gene-gene interaction with the risk of early-onset epilepsy susceptibility, was studied in Chinese children. METHODS: Generalized multi-factor dimension reduction (GMDR) is used to identify the optimal linkage between interaction among four SNPs and early-onset epilepsy susceptibility. Logistic regression was performed to assess association between four SNPs within GRIK2 gene and the risk of epilepsy. RESULTS: The results show that the risk of epilepsy in the rs4840200-T allele carriers was significantly higher than CC (CT/TT vs CC), adjusted OR (95% CI) = 1.74 (1.31-2.20), and the carrier of rs3213607-A allele was also higher than CC (CG/GG vs CC) with adjusted OR (95% CI) = 1.61 (1.23-2.10). We did not detect significant association between rs9390754 and rs2235076 within GRIK2 gene and epilepsy risk. In the GMDR analysis for the gene/gene interaction (2-4 locus models), we found a significant two-locus model (P = 0.001) involving rs4840200 and rs9390754. The cross-validation consistency was 10/10, and the prediction error was 0.632. Participants with rs4840200-CT/TT and rs9390754-GA/AA genotype within GRIK2 gene have the highest epilepsy risk, compared to participants with rs4840200-CC and rs9390754-GG genotype within GRIK2 gene, OR (95% CI) = 2.42 (1.78-3.11), after covariates adjustment for age and gender. CONCLUSIONS: Both rs4840200-T and rs3213607-A, and the interactions between rs4840200 and rs9390754 are related to the increased risk of epilepsy risk.

DPAGT1 Deficiency with Encephalopathy (DPAGT1-CDG): Clinical and Genetic Description of 11 New Patients.

Pathogenic mutations in DPAGT1 cause a rare type of a congenital disorder of glycosylation termed DPAGT1-CDG or, alternatively, a milder version with only myasthenia known as DPAGT1-CMS. Fourteen disease-causing mutations in 28 patients from 10 families have previously been reported to cause the systemic form, DPAGT1-CDG. We here report on another 11 patients from 8 families and add 10 new mutations. Most patients have a very severe disease course, where common findings are pronounced muscular hypotonia, intractable epilepsy, global developmental delay/intellectual disability, and early death. We also present data on three affected females that are young adults and have a somewhat milder, stable disease. Our findings expand both the molecular and clinical knowledge of previously published data but also widen the phenotypic spectrum of DPAGT1-CDG.

Early and long-term electroclinical features of patients with epilepsy and PCDH19 mutation.

Protocadherin 19 (PCDH19) mutations have been identified in epilepsy in females with mental retardation as well as patients with a "Dravet-like" phenotype. We aimed to elucidate the electroclinical phenotype associated with PCDH19 mutation, which is currently difficult to identify at onset leading to a delay in diagnosis. We retrospectively reviewed clinical and EEG data for 13 consecutive patients with PCDH19 mutations or deletions diagnosed at our centers from 2009 to 2011, and followed these patients into adolescence and adulthood. We identified a specific temporal sequence of electroclinical manifestations, identified as three main stages. During the first two years of life, previously healthy girls presented with clusters of afebrile focal seizures. Early seizures were recorded on video-EEG in 10/13 patients, and were focal (n=8) with temporo-occipital and frontal onset. Three patients with strictly stereotyped focal seizures underwent a pre-surgical work-up. Two patients started with generalized seizures, one presenting with early-onset atypical absences and the other generalized tonic-clonic seizures. During the course of the disease, from two to 10 years, seizures became fever-sensitive and continued to recur in clusters, although these were less frequent. Seizures were mainly described by eyewitnesses as generalized tonic-clonic, even though three of five seizures, recorded on EEG, showed a focal onset with fast bilateral spread. Atypical absences and fever-induced tonic-clonic seizures remained frequent in only one patient until the age of 16 years. No specific treatment or combination appeared to be more effective over another. Various degrees of cognitive or behavioural impairment were reported for all patients, but it was in the second decade that behavioural disturbances prevailed with hetero-aggressiveness and behaviour associated with frontal lobe abnormalities leading to psychosis in two. Early recognition of the above features should improve early diagnosis and long-term management of patients with epilepsy and PCDH19 mutations.