Etiological involvement of KCND1 variants in an X-linked neurodevelopmental disorder with variable expressivity.

Utilizing trio whole-exome sequencing and a gene matching approach, we identified a cohort of 18 male individuals from 17 families with hemizygous variants in KCND1, including two de novo missense variants, three maternally inherited protein-truncating variants, and 12 maternally inherited missense variants. Affected subjects present with a neurodevelopmental disorder characterized by diverse neurological abnormalities, mostly delays in different developmental domains, but also distinct neuropsychiatric signs and epilepsy. Heterozygous carrier mothers are clinically unaffected. KCND1 encodes the α-subunit of Kv4.1 voltage-gated potassium channels. All variant-associated amino acid substitutions affect either the cytoplasmic N- or C-terminus of the channel protein except for two occurring in transmembrane segments 1 and 4. Kv4.1 channels were functionally characterized in the absence and presence of auxiliary ß subunits. Variant-specific alterations of biophysical channel properties were diverse and varied in magnitude. Genetic data analysis in combination with our functional assessment shows that Kv4.1 channel dysfunction is involved in the pathogenesis of an X-linked neurodevelopmental disorder frequently associated with a variable neuropsychiatric clinical phenotype.

Relationship between saliva and plasma rufinamide concentrations in patients with epilepsy.

The assay of saliva samples provides a valuable alternative to the use of blood samples for therapeutic drug monitoring (TDM), at least for certain categories of patients. To determine the feasibility of using saliva sampling for the TDM of rufinamide, we compared rufinamide concentrations in paired samples of saliva and plasma collected from 26 patients with epilepsy at steady state. Within-patient relationships between plasma rufinamide concentrations and dose, and the influence of comedication were also investigated. Assay results in the two tested fluids showed a good correlation (r2  = .78, P < .0001), but concentrations in saliva were moderately lower than those in plasma (mean saliva to plasma ratio = 0.7 ± 0.2). In eight patients evaluated at three different dose levels, plasma rufinamide concentrations increased linearly with increasing dose. Patients receiving valproic acid comedication had higher dose-normalized plasma rufinamide levels than patients comedicated with drugs devoid of strong enzyme-inducing or enzyme-inhibiting activity. Overall, these findings indicate that use of saliva represents a feasible option for the application of TDM in patients treated with rufinamide. Because rufinamide concentrations are lower in saliva than in plasma, a correction factor is needed if measurements made in saliva are used as a surrogate for plasma concentrations.

Effect of repetitive transcranial magnetic stimulation on action myoclonus: A pilot study in patients with EPM1.

OBJECTIVE: The objective of this study was to explore the short-term effects of repetitive transcranial magnetic stimulation (rTMS) on action myoclonus. METHODS: Nine patients with Unverricht-Lundborg (EPM1) progressive myoclonus epilepsy type underwent two series of 500 stimuli at 0.3Hz through round coil twice a day for five consecutive days. Clinical and neurophysiological examinations were performed two hours before starting the first rTMS session and two hours after the end of the last rTMS session. RESULTS: Eight patients completed the protocol; one discontinued because of a transient increase in spontaneous jerks. The unified myoclonus rating scale indicated a 25% reduction in posttreatment myoclonus with action score associated with an increase in the cortical motor threshold and lengthening of the cortical silent period (CSP). The decrease in the myoclonus with action scores correlated with the prolongation of CSP. CONCLUSIONS: Repetitive transcranial magnetic stimulation can be safely used in patients with EPM1, improves action myoclonus, and partially restores deficient cortical inhibition.

Confirmation of mutations in PROSC as a novel cause of vitamin B 6 -dependent epilepsy.

Vitamin-B6-dependent epilepsies are a heterogenous group of treatable disorders due to mutations in several genes (ALDH7A1, PNPO, ALPL or ALDH4A1). In neonatal seizures, defects in ALDH7A1 and PNPO explain a major fraction of cases. Very recently biallelic mutations in PROSC were shown to be a novel cause in five families. We identified four further unrelated patients harbouring a total of six different mutations, including four novel disease mutations. Vitamin B6 plasma profiles on pyridoxine did not enable the differentiation of patients with PROSC mutations. All four patients were normocephalic and had normal cranial imaging. Pyridoxine monotherapy allowed complete seizure control in one, while two patients had occasional febrile or afebrile seizures and one needed additional valproate therapy for photosensitive seizures. Two patients underwent a controlled pyridoxine withdrawal with signs of encephalopathy within a couple of days. Three had favourable outcome with normal intellectual properties at age 12.5, 15.5 and 30 years, respectively, while one child had marked developmental delay at age 27 months. The clinical and electroencephalographic phenotype in patients with PROSC mutations was indistinguishable from ALDH7A1 and PNPO deficiency. We therefore confirm PROSC as a novel gene for vitamin-B6-dependent epilepsy and delineate a non-specific plasma vitamin B6 profile under pyridoxine treatment.

Symptomatic and presumed symptomatic focal epilepsies in childhood: An observational, prospective multicentre study.

OBJECTIVE: To describe the clinical, neuropsychological, and psychopathologic features of a cohort of children with a new diagnosis of symptomatic or presumed symptomatic focal epilepsy at time of recruitment and through the first month. The selected population will be followed for 2-5 years after enrollment to investigate the epilepsy course and identify early predictors of drug resistance. METHODS: In this observational, multicenter, nationwide study, children (age 1 month-12.9 years) with a new diagnosis of symptomatic or presumed symptomatic focal epilepsy were consecutively enrolled in 15 Italian tertiary childhood epilepsy centers. Inclusion criteria were as follows: (1) diagnosis of symptomatic focal epilepsy due to acquired and developmental etiologies, and presumed symptomatic focal epilepsy; (2) age at diagnosis older than 1 month and <13 years; and (3) written informed consent. Children were subdivided into three groups: ≤3 years, >3 to 6 years, and >6 years. Clinical, electroencephalography (EEG), neuroimaging, and neuropsychological variables were identified for statistical analyses. RESULTS: Two hundred fifty-nine children were enrolled (116 female and 143 male). Median age: 4.4 years (range 1 month-12.9 years); 46.0% (n = 119) of children were younger than 3 years, 24% (61) from 3 to 6 years of age, and 30% (79) older than 6 years. Neurologic examination findings were normal in 71.8%. Brain magnetic resonance imaging (MRI) was abnormal in 59.9%. Children age ≤3 years experienced the highest seizure frequency in the first month after recruitment (p < 0.0001). Monotherapy in the first month was used in 67.2%. Cognitive tests at baseline revealed abnormal scores in 30%; behavioral problems were present in 21%. At multivariate analysis, higher chances to exhibit more than five seizures in the first month after epilepsy onset was confirmed for younger children and those with temporal lobe epilepsy. SIGNIFICANCE: In this prospective cohort study, an extensive characterization of epilepsy onset in children with symptomatic or presumed symptomatic focal epilepsies is reported in relation to the age group and the localization of the epileptogenic zone.

Myoclonus: Differential diagnosis and current management.

Myoclonus classically presents as a brief (10-50 ms duration), non-rhythmic jerk movement. The etiology could vary considerably ranging from self-limited to chronic or even progressive disorders, the latter falling into encephalopathic pictures that need a prompt diagnosis. Beyond the etiological classification, others evaluate myoclonus' body distribution (i.e., clinical classification) or the location of the generator (i.e., neurophysiological classification); particularly, knowing the anatomical source of myoclonus gives inputs on the observable clinical patterns, such as EMG bursts duration or EEG correlate, and guides the therapeutic choices. Among all the chronic disorders, myoclonus often presents itself as a manifestation of epilepsy. In this context, myoclonus has many facets. Myoclonus occurs as one, or the only, seizure manifestation while it can also present as a peculiar type of movement disorder; moreover, its electroclinical features within specific genetically determined epileptic syndromes have seldom been investigated. In this review, following a meeting of recognized experts, we provide an up-to-date overview of the neurophysiology and nosology surrounding myoclonus. Through the dedicated exploration of epileptic syndromes, coupled with pragmatic guidance, we aim to furnish clinicians and researchers alike with practical advice for heightened diagnostic management and refined treatment strategies. PLAIN LANGUAGE SUMMARY: In this work, we described myoclonus, a movement characterized by brief, shock-like jerks. Myoclonus could be present in different diseases and its correct diagnosis helps treatment.

The history of the concept of epileptic encephalopathy.

The first description of epileptic encephalopathies dates back to Dr. West who, in 1857, described the syndrome that took his name. In addition to West syndrome, in the last century other epileptic syndromes entered into the chapter of epileptic encephalopathies. Henry Gastaut has the virtue of having created the modern concept of epileptic encephalopathy and entering it into the official terminology of the International League Against Epilepsy (ILAE). After the first proposal, it was further defined and refined over time.

Treatment of convulsive status epilepticus in childhood: recommendations of the Italian League Against Epilepsy.

The Italian League Against Epilepsy Commission Guidelines Subcommittee on Status Epilepticus (SE) has published an article on the management of SE in adults, and now presents a report on the management of convulsive status epilepticus (CSE) in children, excluding the neonatal period. Children's greater susceptibility than adults to epileptic seizures results from many factors. Earlier maturation of excitatory than inhibitory synapses, increased susceptibility and concentration of receptors for excitatory neurotransmitters, peculiar composition of the receptor subunits resulting in slower and less effective inhibitory responses, all cause the high incidence of SE in the pediatric population. The related morbidity and mortality rates, although lower than in adults, require immediate diagnosis and therapy. The division into focal and generalized, nonconvulsive and convulsive SE is applied in children and adolescents, as is the distinction in the three different stages according to the time elapsed since the start of the event and the response to drugs (initial, defined, and refractory SE). In children and adolescents, an "operational definition" is also accepted to allow earlier treatment (starting at 5-10 min). Maintenance and stabilization of vital functions, cessation of convulsions, diagnosis, and initial treatment of potentially "life-threatening" causes are the objectives to be pursued in the management of children with CSE. The need for early pharmacologic intervention stresses the need for action in the prehospital setting, generally using rectal diazepam. In hospital, parenteral benzodiazepines are used (lorazepam, diazepam, or midazolam). When first-line drugs fail, sodium phenytoin and phenobarbital should be used. As alternatives to phenobarbital, the following can be considered for treatment of refractory CSE: valproate, levetiracetam, and lacosamide. In cases with refractory CSE, pharmacologic options can be thiopental, midazolam, or propofol in continuous intravenous infusions to suppress electroencephalographic bursts and convulsive activity. These drugs need to be administered in intensive care units to ensure the monitoring and support of vital signs and brain electrical activity.

Genetic testing in benign familial epilepsies of the first year of life: clinical and diagnostic significance.

PURPOSE: To dissect the genetics of benign familial epilepsies of the first year of life and to assess the extent of the genetic overlap between benign familial neonatal seizures (BFNS), benign familial neonatal-infantile seizures (BFNIS), and benign familial infantile seizures (BFIS). METHODS: Families with at least two first-degree relatives affected by focal seizures starting within the first year of life and normal development before seizure onset were included. Families were classified as BFNS when all family members experienced neonatal seizures, BFNIS when the onset of seizures in family members was between 1 and 4 months of age or showed both neonatal and infantile seizures, and BFIS when the onset of seizures was after 4 months of age in all family members. SCN2A, KCNQ2, KCNQ3, PPRT2 point mutations were analyzed by direct sequencing of amplified genomic DNA. Genomic deletions involving KCNQ2 and KCNQ3 were analyzed by multiple-dependent probe amplification method. KEY FINDINGS: A total of 46 families including 165 affected members were collected. Eight families were classified as BFNS, 9 as BFNIS, and 29 as BFIS. Genetic analysis led to the identification of 41 mutations, 14 affecting KCNQ2, 1 affecting KCNQ3, 5 affecting SCN2A, and 21 affecting PRRT2. The detection rate of mutations in the entire cohort was 89%. In BFNS, mutations specifically involve KCNQ2. In BFNIS two genes are involved (KCNQ2, six families; SCN2A, two families). BFIS families are the most genetically heterogeneous, with all four genes involved, although about 70% of them carry a PRRT2 mutation. SIGNIFICANCE: Our data highlight the important role of KCNQ2 in the entire spectrum of disorders, although progressively decreasing as the age of onset advances. The occurrence of afebrile seizures during follow-up is associated with KCNQ2 mutations and may represent a predictive factor. In addition, we showed that KCNQ3 mutations might be also involved in families with infantile seizures. Taken together our data indicate an important role of K-channel genes beyond the typical neonatal epilepsies. The identification of a novel SCN2A mutation in a family with infantile seizures with onset between 6 and 8 months provides further confirmation that this gene is not specifically associated with BFNIS and is also involved in families with a delayed age of onset. Our data indicate that PRRT2 mutations are clustered in families with BFIS. Paroxysmal kinesigenic dyskinesia emerges as a distinctive feature of PRRT2 families, although uncommon in our series. We showed that the age of onset of seizures is significantly correlated with underlying genetics, as about 90% of the typical BFNS families are linked to KCNQ2 compared to only 3% of the BFIS families, for which PRRT2 represents the major gene.

Clinical dissection of early onset absence epilepsy in children and prognostic implications.

PURPOSE: To investigate whether patients with typical absence seizures (TAS) starting in the first 3 years of life, conformed to Panayiotopoulos's definition of childhood absence epilepsy (CAE), show different electroclinical course than those not fulfilling CAE criteria. METHODS: In this multicenter retrospective study, we choose a fixed duration follow-up of 36 months to examine the electroclinical course of epilepsy in all children with TAS starting before 3 years of age. The probands who fulfilled Panayiotopoulos's criteria for CAE were classified as having pure early onset absence epilepsy (P-EOAE), whereas those who did not as nonpure EOAE (NP-EOAE). In addition, these two groups of patients were further stratified according to the number of antiepileptic drugs taken to obtain initial seizure control (mono-, bi-, and tritherapy). KEY FINDINGS: Patients with P-EOAE (n = 111) showed earlier initial seizure control (p = 0.030) and better seizure-free survival curve (p = 0.004) than those with NP-EOAE (n = 77). No mutation in SLC2A1 gene or abnormal neuroimaging was observed in P-EOAE. Among patients with NP-EOAE, those receiving tritherapy showed increased risk of structural brain abnormalities (p = 0.001) or SLC2A1 mutations (p = 0.001) but fewer myoclonic features (p = 0.031) and worse seizure-free survival curve (p = 0.047) than those treated with mono- and bitherapy. Children with NP-EOAE had 2.134 the odds of having relapse during the follow-up compare to those with P-EOAE. SIGNIFICANCE: Children with early onset TAS who did meet Panayiotopoulos's criteria showed a favorable course of epilepsy, whereas patients not fulfilling Panayiotopoulos's criteria showed increased risk of relapse at long-term follow-up.

Head atonic attacks: a new type of benign non-epileptic attack in infancy strongly mimicking epilepsy.

Non-epileptic attacks (NEAs) are a heterogeneous group of clinical entities which often complicate the differential diagnosis of epilepsy. NEAs usually have a benign course and are limited to a specific period of life. If motor manifestations are strongly suggestive of an epileptic phenomenon, the risk of misdiagnosis is greater. Here, we describe a novel NEA with infantile onset, characterised by repeated head drops, mimicking epileptic negative myoclonus of the neck. The frequency of the episodes was very high, at hundreds or thousands per day. The episodes appeared in the second semester of the first year of life and spontaneously disappeared within a few months. [Published with video sequences].

Increased cortical BOLD signal anticipates generalized spike and wave discharges in adolescents and adults with idiopathic generalized epilepsies.

PURPOSE: Electroencephalography-functional magnetic resonance imaging (EEG-fMRI) coregistration has recently revealed that several brain structures are involved in generalized spike and wave discharges (GSWDs) in idiopathic generalized epilepsies (IGEs). In particular, deactivations and activations have been observed within the so-called brain default mode network (DMN) and thalamus, respectively. In the present study we analyzed the dynamic time course of blood oxygen level-dependent (BOLD) changes preceding and following 3 Hz GSWDs in a group of adolescent and adult patients with IGE who presented with absence seizures (AS). Our aim was to evaluate cortical BOLD changes before, during, and after GSWD onset. METHODS: Twenty-one patients with IGE underwent EEG-fMRI coregistration. EEG-related analyses were run both at the single-subject and at group level (random effect). The time-course analysis was conducted for 3 s time windows before, during, and after GSWDs, and they were included until no further BOLD signal changes were observed. KEY FINDINGS: Fifteen patients (nine female, mean age 28 years) had GSWDs during EEG-fMRI coregistration (262 total events, mean duration 4 s). Time-course group analysis showed BOLD increments starting approximately 10 s before GSWD onset located in frontal and parietal cortical areas, and especially in the precuneus-posterior cingulate region. At GSWD onset, BOLD increments were located in thalamus, cerebellum, and anterior cingulate gyrus, whereas BOLD decrements were observed in the DMN regions persisting until 9 s after onset. SIGNIFICANCE: Hemodynamic changes (BOLD increments) occurred in specific cortical areas, namely the precuneus/posterior cingulate, lateral parietal, and frontal cortices, several seconds before EEG onset of GSWD. A dysfunction of these brain regions, some of which belongs to the DMN, may be crucial in generating GSWDs in patients with IGE.

Electroclinical presentation and genotype-phenotype relationships in patients with Unverricht-Lundborg disease carrying compound heterozygous CSTB point and indel mutations.

PURPOSE: Unverricht-Lundborg disease (EPM1A) is frequently due to an unstable expansion of a dodecamer repeat in the CSTB gene, whereas other types of mutations are rare. EPM1A due to homozygous expansion has a rather stereotyped presentation with prominent action myoclonus. We describe eight patients with five different compound heterozygous CSTB point or indel mutations in order to highlight their particular phenotypical presentations and evaluate their genotype-phenotype relationships. METHODS: We screened CSTB mutations by means of Southern blotting and the sequencing of the genomic DNA of each proband. CSTB messenger RNA (mRNA) aberrations were characterized by sequencing the complementary DNA (cDNA) of lymphoblastoid cells, and assessing the protein concentrations in the lymphoblasts. The patient evaluations included the use of a simplified myoclonus severity rating scale, multiple neurophysiologic tests, and electroencephalography (EEG)-polygraphic recordings. To highlight the particular clinical features and disease time-course in compound heterozygous patients, we compared some of their characteristics with those observed in a series of 40 patients carrying the common homozygous expansion mutation observed at the C. Besta Foundation, Milan, Italy. KEY FINDINGS: The eight compound heterozygous patients belong to six EPM1A families (out of 52; 11.5%) diagnosed at the Laboratory of Genetics of the Galliera Hospitals in Genoa, Italy. They segregated five different heterozygous point or indel mutations in association with the common dodecamer expansion. Four patients from three families had previously reported CSTB mutations (c.67-1G>C and c.168+1_18del); one had a novel nonsense mutation at the first exon (c.133C>T) leading to a premature stop codon predicting a short peptide; the other three patients from two families had a complex novel indel mutation involving the donor splice site of intron 2 (c.168+2_169+21delinsAA) and leading to an aberrant transcript with a partially retained intron. The protein dose (cystatin B/ß-actin) in our heterozygous patients was 0.24 ± 0.02, which is not different from that assessed in patients bearing the homozygous dodecamer expansion. The compound heterozygous patients had a significantly earlier disease onset (7.4 ± 1.7 years) than the homozygous patients, and their disease presentations included frequent myoclonic seizures and absences, often occurring in clusters throughout the course of the disease. The seizures were resistant to the pharmacologic treatments that usually lead to complete seizure control in homozygous patients. EEG-polygraphy allowed repeated seizures to be recorded. Action myoclonus progressively worsened and all of the heterozygous patients older than 30 years were in wheelchairs. Most of the patients showed moderate to severe cognitive impairment, and six had psychiatric symptoms. SIGNIFICANCE: EPM1A due to compound heterozygous CSTB mutations presents with variable but often markedly severe and particular phenotypes. Most of our patients presented with the electroclinical features of severe epilepsy, which is unexpected in homozygous patients, and showed frequent seizures resistant to pharmacologic treatment. The presence of variable phenotypes (even in siblings) suggests interactions with other genetic factors influencing the final disease presentation.

Genome-wide linkage meta-analysis identifies susceptibility loci at 2q34 and 13q31.3 for genetic generalized epilepsies.

PURPOSE: Genetic generalized epilepsies (GGEs) have a lifetime prevalence of 0.3% with heritability estimates of 80%. A considerable proportion of families with siblings affected by GGEs presumably display an oligogenic inheritance. The present genome-wide linkage meta-analysis aimed to map: (1) susceptibility loci shared by a broad spectrum of GGEs, and (2) seizure type-related genetic factors preferentially predisposing to either typical absence or myoclonic seizures, respectively. METHODS: Meta-analysis of three genome-wide linkage datasets was carried out in 379 GGE-multiplex families of European ancestry including 982 relatives with GGEs. To dissect out seizure type-related susceptibility genes, two family subgroups were stratified comprising 235 families with predominantly genetic absence epilepsies (GAEs) and 118 families with an aggregation of juvenile myoclonic epilepsy (JME). To map shared and seizure type-related susceptibility loci, both nonparametric loci (NPL) and parametric linkage analyses were performed for a broad trait model (GGEs) in the entire set of GGE-multiplex families and a narrow trait model (typical absence or myoclonic seizures) in the subgroups of JME and GAE families. KEY FINDINGS: For the entire set of 379 GGE-multiplex families, linkage analysis revealed six loci achieving suggestive evidence for linkage at 1p36.22, 3p14.2, 5q34, 13q12.12, 13q31.3, and 19q13.42. The linkage finding at 5q34 was consistently supported by both NPL and parametric linkage results across all three family groups. A genome-wide significant nonparametric logarithm of odds score of 3.43 was obtained at 2q34 in 118 JME families. Significant parametric linkage to 13q31.3 was found in 235 GAE families assuming recessive inheritance (heterogeneity logarithm of odds = 5.02). SIGNIFICANCE: Our linkage results support an oligogenic predisposition of familial GGE syndromes. The genetic risk factor at 5q34 confers risk to a broad spectrum of familial GGE syndromes, whereas susceptibility loci at 2q34 and 13q31.3 preferentially predispose to myoclonic seizures or absence seizures, respectively. Phenotype- genotype strategies applying narrow trait definitions in phenotypic homogeneous subgroups of families improve the prospects of disentangling the genetic basis of common familial GGE syndromes.

Photosensitivity: epidemiology, genetics, clinical manifestations, assessment, and management.

Photosensitivity is a genetically determined trait that may be asymptomatic throughout life or manifest with epileptic seizures. Photosensitivity usually begins before the age of 20 years with a peak age at onset at around 12. Both natural and artificial light may trigger seizures. Precise investigation must be carried out by intermittent photic stimulation that can elicit a clearly defined EEG response; video-EEG samples are reported to illustrate the various determinants of response and the main factors altering the effectiveness of intermittent photic stimulation. Management of photosensitive epilepsy includes non-pharmacological (e.g. avoidance of the provocative stimuli and wearing appropriate tinted glass) and pharmacological treatment. This review focuses on the emerging aspects of photosensitivity, in particular, the new guidelines for intermittent photic stimulation and briefly addresses epidemiological (in non-epileptic and epileptic subjects), genetic, diagnostic, and therapeutic issues. [Published with video sequences].

Epilepsy Course and Developmental Trajectories in STXBP1-DEE.

Background and Objectives: Clinical manifestations in STXBP1 developmental and epileptic encephalopathy (DEE) vary in severity and outcome, and the genotypic spectrum is diverse. We aim to trace the neurodevelopmental trajectories in individuals with STXBP1-DEE and dissect the relationship between neurodevelopment and epilepsy. Methods: Retrospective standardized clinical data were collected through international collaboration. A composite neurodevelopmental score system compared the developmental trajectories in STXBP1-DEE. Results: Forty-eight patients with de novo STXBP1 variants and a history of epilepsy were included (age range at the time of the study: 10 months to 35 years, mean 8.5 years). At the time of inclusion, 65% of individuals (31/48) had active epilepsy, whereas 35% (17/48) were seizure free, and 76% of those (13/17) achieved remission within the first year of life. Twenty-two individuals (46%) showed signs of developmental impairment and/or neurologic abnormalities before epilepsy onset. Age at seizure onset correlated with severity of developmental outcome and the developmental milestones achieved, with a later seizure onset associated with better developmental outcome. In contrast, age at seizure remission and epilepsy duration did not affect neurodevelopmental outcomes. Overall, we did not observe a clear genotype-phenotype correlation, but monozygotic twins with de novo STXBP1 variant showed similar phenotype and parallel disease course. Discussion: The disease course in STXBP1-DEE presents with 2 main trajectories, with either early seizure remission or drug-resistant epilepsy, and a range of neurodevelopmental outcomes from mild to profound intellectual disability. Age at seizure onset is the only epilepsy-related feature associated with neurodevelopment outcome. These findings can inform future dedicated natural history studies and trial design.

A functional polymorphism in the SCN1A gene does not influence antiepileptic drug responsiveness in Italian patients with focal epilepsy.

A splice site variation (c.603-91G>A or rs3812718) in the SCN1A gene has been claimed to influence efficacy and dose requirements of carbamazepine and phenytoin. We investigated the relationship between c.603-91G>A polymorphism and response to antiepileptic drugs (AEDs) in 482 patients with drug-resistant and 401 patients with drug-responsive focal epilepsy. Most commonly used AEDs were carbamazepine and oxcarbazepine. The distribution of c.603-91G>A genotypes was similar among drug-resistant and drug-responsive subjects, both in the entire population and in the groups treated with carbamazepine or oxcarbazepine. There was no association between the c.603-91G>A genotype and dosages of carbamazepine or oxcarbazepine. These findings rule out a major role of the SCN1A polymorphism as a determinant of AED response.

Clinical spectrum and genotype-phenotype correlations in PRRT2 Italian patients.

Prrt2 is a neuron-specific protein expressed at axonal and pre-synaptic domains, involved in synaptic neurotransmitter release and modulation of intrinsic excitability. Mutations in PRRT2 cause a spectrum of autosomal dominant paroxysmal neurological disorders including epilepsy, movement disorders, and hemiplegic migraine and show incomplete penetrance and variable expressivity. We assessed the diagnostic rate of PRRT2 in a cohort of Italian patients with epilepsy and/or paroxysmal kinesigenic dyskinesia (PKD) and evaluated genotype-phenotype correlations. Clinical data were collected using a structured questionnaire. Twenty-seven out of 55 (49.1%) probands carried PRRT2 heterozygous pathogenic variants, including six previously known genotypes and one novel missense mutation. A family history of epilepsy starting in the first year of life and/or PKD was strongly suggestive of a PRRT2 pathogenic variant. Epilepsy patients harbouring PRRT2 pathogenic variants showed earlier seizure onset and more frequent clusters compared with PRRT2-negative individuals with epilepsy. Moreover, we did also identify individuals with PRRT2 pathogenic variants with atypical age at onset, i.e. childhood-onset epilepsy and infantile-onset PKD. However, the lack of a clear correlation between specific PRRT2 genotypes and clinical manifestations and the high incidence of asymptomatic carriers suggest the involvement of additional factors in modulating expressivity of PRRT2-related disorders. Finally, our study supports the pleiotropic and multifaceted physiological role of PRRT2 gene which is emerging from experimental neuroscience.

Changes in Panayiotopoulos syndrome over time.

In its first description (1989), Panayiotopoulos syndrome was defined as an idiopathic epilepsy syndrome with an excellent prognosis, characterized by a clinical ictal triad of nocturnal seizures, tonic deviation of the eyes, and vomiting. The electroencephalographic and clinical features of this condition were highly suggestive of occipital lobe involvement. Subsequently, the concept of this benign age-related focal epilepsy has been expanded over the years, including a wider and larger spectrum of seizure manifestations far beyond the occipital manifestations, and for which the eponym of Panayiotopoulos syndrome (PS) has been adopted. However, many theoretical and practical points, including diagnostic, genetic, and pathophysiologic issues remain still unresolved for PS.

The spectrum of benign myoclonus of early infancy: Clinical and neurophysiologic features in 102 patients.

PURPOSE: To redefine benign myoclonus of early infancy (BMEI) through analysis of clinical and neurophysiologic features in 102 patients with the aim to widen the spectrum of the syndrome, including a number of different clinical expressions of transient nonepileptic paroxysmal movements occurring in normal infants. METHODS: We recruited patients from one center in Argentina and two in Italy, including infants with normal neurologic and psychomotor development presenting with brief paroxysmal abnormal movements. Children with motor phenomena occurring only during sleep were excluded. Patients with abnormal interictal or ictal electroencephalography (EEG) findings were also excluded. The follow-up ranged from 2-40 years. RESULTS: One hundred and two infants (60 male) met the inclusion criteria. Age at onset ranged from 1-12 months, with a median age of 6.2 months. The following nonepileptic paroxysmal motor phenomena were recognized: (1) myoclonus, (2) spasms and brief tonic contractions, (3) shuddering, (4) atonia or negative myoclonus, (5) more than one type of motor phenomenon. In the majority of cases the episodes occurred only while awake and repeated several times a day. In 45 (44.1%) of the 102 cases contractions appeared in clusters. CONCLUSIONS: Based on the analysis of clinical and EMG features in this large series of infants, we postulate that the spectrum of the syndrome is wider than initially suspected, and that the different transient motor manifestations and their correlation with different EMG patterns will allow recognition of this definitely benign condition comprising a variety of episodic motor phenomena in normal babies.