Symptomatology of carbamazepine- and oxcarbazepine-induced hyponatremia in people with epilepsy.

OBJECTIVE: To ascertain whether adverse effects experienced by people taking carbamazepine or oxcarbazepine could be attributed to carbamazepine- or oxcarbazepine-induced hyponatremia (COIH). METHODS: We performed an observational study, collecting data between 2017 and 2019 on serum sodium levels and adverse effects retrospectively in people with epilepsy while receiving treatment with either carbamazepine (CBZ) or oxcarbazepine (OXC). We defined hyponatremia as sodium level ≤134 mEq/L and severe hyponatremia as sodium level ≤128 mEq/L. Adverse effects experienced were compared between groups of individuals with and without hyponatremia. RESULTS: A total of 1370 people using CBZ or OXC were identified, of whom 410 had at least one episode of hyponatremia. We checked for symptoms related to the use of CBZ and OXC in 710 people (410 with and 300 without hyponatremia) and found relevant information in 688. Adverse effects occurred in 65% of people with hyponatremia compared to 21% with normal sodium levels (odds ratio [OR] 7.5, P ≤ .001) and in 83% of people with severe hyponatremia compared to 55% in those with mild hyponatremia (P ≤ .001). Significant predictors of adverse effects were the drug (OXC vs CBZ), and the number of concomitant anti-seizure medications. Dizziness (28% vs 6%), tiredness (22% vs 7%), instability (19% vs 3%), and diplopia (16% vs 4%) were reported more often in the hyponatremia group than in patients with normal levels. SIGNIFICANCE: People with COIH had a 7-fold increased risk of developing adverse effects during treatment. Clinicians should consider ascertainment of sodium levels in patients taking CBZ and OXC and act upon findings.

Well-being of mothers with epilepsy with school-aged children.

PURPOSE: The purpose of the study was to examine different aspects of well-being in mothers with epilepsy with school-aged children. METHODS: In an observational study, mothers, identified from the European Registry of Antiepileptic Drugs and Pregnancy database in the Netherlands, completed questions on epilepsy, the impact of epilepsy on daily functioning, quality of life, behavioral problems, and parenting stress. Descriptive analyses were performed to examine the prevalence of behavioral problems and the impact of epilepsy on different aspects of the mother's daily functioning and family life. We subsequently investigated which factors contributed most to the impact of maternal epilepsy using regression analyses. RESULTS: One hundred fifty-six (46%) of the 342 invited mothers with epilepsy participated. The majority (89%) had low epilepsy severity, with well-controlled seizures. Internalizing problems within the borderline or clinical range were reported by 23% of the mothers. Behavioral problems were significantly correlated with epilepsy severity (r = 0.26, p = .002), impact of epilepsy on daily functioning (r = 0.32, p < .001), and quality of life (r = -0.52, p < 01). Quality of life was in general good (mean = 8, standard deviation [SD] = 1), with low impact of epilepsy. Epilepsy affected mostly maternal self-confidence, work, and general health. Mothers indicated to experience no to little impact of epilepsy on the relationship with their children, partner, or family. Regression analyses showed that epilepsy severity (1.0, 95% confidence interval [CI]: 0.4 to 1.6; p = .002) and quality of life (-1.3, CI: -2.3 to -0.4; p = .007) were significant contributors to the impact of epilepsy on daily functioning, while other factors (maternal education, family type, behavioral problems, and parenting stress) were nonsignificant. DISCUSSION: The current study shows that mothers with epilepsy generally fared well. Epilepsy negatively impacted the lives of some mothers, though. As maternal well-being is of importance for mother-child interaction and child development, clinicians should be aware of the impact of epilepsy on maternal psychosocial outcomes and family life of women with epilepsy.

Behavioral problems in children of mothers with epilepsy prenatally exposed to valproate, carbamazepine, lamotrigine, or levetiracetam monotherapy.

OBJECTIVE: To examine the behavioral functioning of children prenatally exposed to carbamazepine (CBZ), lamotrigine (LTG), levetiracetam (LEV), or valproate (VPA) monotherapy. METHODS: In collaboration with the European Registry of Antiepileptic Drugs and Pregnancy (EURAP), the Dutch EURAP & Development study was designed, a prospective observational study. Between January 2015 and March 2018, the Child Behavior Checklist and the Social Emotional Questionnaire were used to examine the nature and severity of behavioral problems. VPA-exposed children were compared to children exposed to CBZ, LTG, or LEV, taking potential confounders into account. A direct comparison was also made between LTG and LEV, as these are first-choice treatments for many women with epilepsy of childbearing potential. RESULTS: Of the 405 invited, 181 children were included; 26 were exposed to VPA, 37 to CBZ, 88 to LTG, and 30 to LEV. For most children, both parents completed the behavioral questionnaires. Across all four antiepileptic drug (AED) exposure groups, high percentages of children with clinically relevant behavior problems were found, with behavioral problems occurring in 32% of VPA-exposed children, 14% of CBZ, 16% of LTG, and 14% of LEV. After controlling for potential confounders, VPA-exposed children had significantly more social problems than those exposed to LTG (-2.8, 95% confidence interval [CI] = -5.2 to -0.4; P = 0.022) or LEV (-3.2, CI: -6.1 to -0.3; P = 0.028), and significantly more attention problems than LEV-exposed children (-3.7, CI: -6.7 to -0.8; P = 0.013). LTG-exposed children had significantly more attention deficit (-9.2, CI: -17.3 to 1.1; P = 0.026), but significantly less anxious behavior when compared to LEV-exposed children (9.0, CI: 0.3-17.6; P = 0.042). SIGNIFICANCE: Compared to population norms, a high proportion of children of mothers with epilepsy exposed prenatally to monotherapy with four common AEDs had clinical behavioral problems reported by parents. Different patterns were seen, with some but not all subscales raised for all AED exposure groups. It is important that prenatally AED-exposed children are regularly screened for behavioral problems so that appropriate help can be provided.

Maternal epilepsy and behavioral development of the child: Family factors do matter.

PURPOSE: The purpose of the study was to examine whether mothers with epilepsy experience family problems and to investigate the possible mediating role of distinct family factors in the relationship between maternal epilepsy and child behavioral problems, in which it is also investigated whether more proximal family factors mediate the more distal family factors. METHODS: In an observational study, with children identified from the European Registry of Antiepileptic Drugs and Pregnancy database in the Netherlands (EURAP-NL), parents completed questionnaires on maternal epilepsy, family factors (proximal, distal, contextual, global), and child behavior. Hierarchical multilevel regression analyses were performed to examine the relative contribution of epilepsy-related and family factors on child internalizing and externalizing problems. RESULTS: Between January 2015 and March 2018, the questionnaires were completed for 175 children. Mothers with epilepsy showed significantly more parenting stress and problems with parenting than mothers from the general population. Family factors were significantly associated with child behavioral problems. For internalizing problems, maternal epilepsy, global, contextual, and distal family factors were each found to have significant added value. Distal family factors contributed most to internalizing problems and showed a mediating role for epilepsy-related factors and previous added family factors in the model. Global, contextual, distal, and proximal factors were all found to be significant contributors to externalizing problems, with the factor most proximal to the child (quality of parent-child interaction) showing the largest effect. DISCUSSION: Including family factors in research regarding children of mothers with epilepsy is important as they can have a contribution additional to the teratogenic risks of prenatal exposure to antiepileptic drugs (AEDs). Family factors, in particular distal and proximal family factors, can weaken or strengthen child development and may provide starting points for interventions.

Exposure to antiepileptic drugs in pregnancy: The need for a family factor framework.

PURPOSE: Children exposed to antiepileptic drugs (AEDs) in utero are at risk for developmental problems. Maternal epilepsy, its impact on the family system, and other family factors may also contribute. We reviewed the possible associations between family factors and developmental outcome in children who had been exposed to AED during pregnancy. METHODS: We conducted a narrative review and searched MEDLINE, Embase, Google Scholar, and PsycINFO on the following terms: in utero exposure, pregnancy outcome, and AEDs. A family factor framework (the ABCX model) served as the basis to review distinct family factors in children who were exposed to AEDs in pregnancy. RESULTS: Few studies have investigated these factors. Mothers with epilepsy have problems caring for themselves and for the child and experience more parenting stress. There is a paucity of studies of the possible impact of family factors on the neurocognitive and behavioral development of children of mothers with epilepsy. DISCUSSION: Further work is required to ascertain which family factors are associated with child development in addition to the effects of AED exposure and their potential interaction. As epilepsy may have considerable impact on intrafamily factors and as children are especially vulnerable to such effects, study designs incorporating family factors should be encouraged.

Burden analysis of rare microdeletions suggests a strong impact of neurodevelopmental genes in genetic generalised epilepsies.

Genetic generalised epilepsy (GGE) is the most common form of genetic epilepsy, accounting for 20% of all epilepsies. Genomic copy number variations (CNVs) constitute important genetic risk factors of common GGE syndromes. In our present genome-wide burden analysis, large (≥ 400 kb) and rare (< 1%) autosomal microdeletions with high calling confidence (≥ 200 markers) were assessed by the Affymetrix SNP 6.0 array in European case-control cohorts of 1,366 GGE patients and 5,234 ancestry-matched controls. We aimed to: 1) assess the microdeletion burden in common GGE syndromes, 2) estimate the relative contribution of recurrent microdeletions at genomic rearrangement hotspots and non-recurrent microdeletions, and 3) identify potential candidate genes for GGE. We found a significant excess of microdeletions in 7.3% of GGE patients compared to 4.0% in controls (P = 1.8 x 10-7; OR = 1.9). Recurrent microdeletions at seven known genomic hotspots accounted for 36.9% of all microdeletions identified in the GGE cohort and showed a 7.5-fold increased burden (P = 2.6 x 10-17) relative to controls. Microdeletions affecting either a gene previously implicated in neurodevelopmental disorders (P = 8.0 x 10-18, OR = 4.6) or an evolutionarily conserved brain-expressed gene related to autism spectrum disorder (P = 1.3 x 10-12, OR = 4.1) were significantly enriched in the GGE patients. Microdeletions found only in GGE patients harboured a high proportion of genes previously associated with epilepsy and neuropsychiatric disorders (NRXN1, RBFOX1, PCDH7, KCNA2, EPM2A, RORB, PLCB1). Our results demonstrate that the significantly increased burden of large and rare microdeletions in GGE patients is largely confined to recurrent hotspot microdeletions and microdeletions affecting neurodevelopmental genes, suggesting a strong impact of fundamental neurodevelopmental processes in the pathogenesis of common GGE syndromes.

Carbamazepine- and oxcarbazepine-induced hyponatremia in people with epilepsy.

OBJECTIVE: To ascertain possible determinants of carbamazepine (CBZ)- and oxcarbazepine (OXC)-induced hyponatremia in a large cohort of people with epilepsy. METHODS: We collected data on serum sodium levels in people with epilepsy who were attending a tertiary epilepsy center while on treatment with CBZ or OXC. We defined hyponatremia as Na+ ≤134 mEq/L and severe hyponatremia as Na+ ≤128 mEq/L. RESULTS: We identified 1,782 people who had used CBZ (n = 1,424) or OXC (n = 358), of whom 50 were treated with both drugs. Data on sodium level measurements were available in 1,132 on CBZ and in 289 on OXC. Hyponatremia occurred in 26% of those taking CBZ and 46% of those taking OXC. This was severe in 7% in the CBZ group and 22% in the OXC group. Hyponatremia was symptomatic in 48% and led to admissions in 3%. Age over 40 years, high serum levels of CBZ and OXC, and concomitant use of other antiepileptic drugs were the main risk factors for hyponatremia in both treatment groups. Female patients on OXC were at a higher risk than male patients of hyponatremia. The risk of hyponatremia on CBZ was significantly associated with the risk of hyponatremia on OXC within a subgroup that used both drugs consecutively. SIGNIFICANCE: Hyponatremia is a common problem in people taking CBZ or OXC. Regular ascertainment of sodium levels in those taking either drug is recommended and results should be acted on.

Withdrawal of valproic acid treatment during pregnancy and seizure outcome: Observations from EURAP.

Based on data from the EURAP observational International registry of antiepileptic drugs (AEDs) and pregnancy, we assessed changes in seizure control and subsequent AED changes in women who underwent attempts to withdraw valproic acid (VPA) during the first trimester of pregnancy. Applying Bayesian statistics, we compared seizure control in pregnancies where VPA was withdrawn (withdrawal group, n = 93), switched to another AED (switch group, n = 38), or maintained (maintained-therapy group, n = 1,588) during the first trimester. The probability of primarily or secondarily generalized tonic-clonic seizures (GTCS) was lower in the maintained-therapy group compared with the other two groups, both in the first trimester and for the entire duration of pregnancy. GTCS were twice as common during pregnancy in the withdrawal (33%) and switch groups (29%) compared with the maintained-treatment group (16%). Limitations in the data and study design do not allow to establish a cause-effect relationship between treatment changes and seizure outcome, but these observations provide a signal that withdrawal of, or switch from, VPA during the first trimester could lead to loss of seizure control, and highlight the need for a specifically designed prospective observational study.

Seizure precipitants in Dravet syndrome: What events and activities are specifically provocative compared with other epilepsies?

OBJECTIVES: This study aimed to describe seizure precipitants in Dravet syndrome (DS) compared with other epilepsies. METHODS: Seizure precipitants as reported in a Dutch cohort of patients with DS with pathogenic SCN1A mutations (n=71) were compared with those of a cohort with childhood epilepsy (n=149) and of a community-based cohort with epilepsy (n=248); for all three Dutch cohorts, the same type of questionnaire was used. Seizure precipitants were categorized as 'fever', 'visual stimuli', 'sleep deprivation', 'stress, including physical exercise', 'auditory stimuli', and 'other'. RESULTS: For 70 (99%) of 71 patients with DS, at least one seizure precipitant was recalled by parents. Seizure precipitants that were reported in more than half of the cohort with DS were as follows: having a fever (97%), having a cold (68%), taking a bath (61%), having acute moments of stress (58%), and engaging in physical exercise (56%). Seizure precipitants freely recalled by parents were often related to ambient warmth or cold-warmth shifts (41%) and to various visual stimuli (18%). Patients with DS had more positive seizure precipitant categories (median 4) compared with the cohort with childhood epilepsy (median 2) and the community-based cohort with epilepsy (median 0) (p<0.001) and showed the highest percentage in each category (all p<0.001). Within the category 'stress, including physical exercise', physical exercise was more often reported to provoke seizures in stress-sensitive patients in the cohort with DS than in the cohort with childhood epilepsy (78% vs. 35%, p<0.001). In the cohort with childhood epilepsy, physical exercise was more often reported in fever-sensitive children than in other children (25% vs. 12%, p=0.042). CONCLUSIONS: Our study shows a high prevalence of a range of seizure precipitants in DS. Our results underscore elevated body temperature as an important seizure precipitant, whether caused by fever, warm bath, ambient warmth, or physical exercise. Knowledge of these seizure precipitants may improve preventive strategies in the otherwise difficult treatment of DS.

Genome-wide association analysis of genetic generalized epilepsies implicates susceptibility loci at 1q43, 2p16.1, 2q22.3 and 17q21.32.

Genetic generalized epilepsies (GGEs) have a lifetime prevalence of 0.3% and account for 20-30% of all epilepsies. Despite their high heritability of 80%, the genetic factors predisposing to GGEs remain elusive. To identify susceptibility variants shared across common GGE syndromes, we carried out a two-stage genome-wide association study (GWAS) including 3020 patients with GGEs and 3954 controls of European ancestry. To dissect out syndrome-related variants, we also explored two distinct GGE subgroups comprising 1434 patients with genetic absence epilepsies (GAEs) and 1134 patients with juvenile myoclonic epilepsy (JME). Joint Stage-1 and 2 analyses revealed genome-wide significant associations for GGEs at 2p16.1 (rs13026414, P(meta) = 2.5 × 10(-9), OR[T] = 0.81) and 17q21.32 (rs72823592, P(meta) = 9.3 × 10(-9), OR[A] = 0.77). The search for syndrome-related susceptibility alleles identified significant associations for GAEs at 2q22.3 (rs10496964, P(meta) = 9.1 × 10(-9), OR[T] = 0.68) and at 1q43 for JME (rs12059546, P(meta) = 4.1 × 10(-8), OR[G] = 1.42). Suggestive evidence for an association with GGEs was found in the region 2q24.3 (rs11890028, P(meta) = 4.0 × 10(-6)) nearby the SCN1A gene, which is currently the gene with the largest number of known epilepsy-related mutations. The associated regions harbor high-ranking candidate genes: CHRM3 at 1q43, VRK2 at 2p16.1, ZEB2 at 2q22.3, SCN1A at 2q24.3 and PNPO at 17q21.32. Further replication efforts are necessary to elucidate whether these positional candidate genes contribute to the heritability of the common GGE syndromes.

A new coding system for metabolic disorders demonstrates gaps in the international disease classifications ICD-10 and SNOMED-CT, which can be barriers to genotype-phenotype data sharing.

Data sharing is essential for a better understanding of genetic disorders. Good phenotype coding plays a key role in this process. Unfortunately, the two most widely used coding systems in medicine, ICD-10 and SNOMED-CT, lack information necessary for the detailed classification and annotation of rare and genetic disorders. This prevents the optimal registration of such patients in databases and thus data-sharing efforts. To improve care and to facilitate research for patients with metabolic disorders, we developed a new coding system for metabolic diseases with a dedicated group of clinical specialists. Next, we compared the resulting codes with those in ICD and SNOMED-CT. No matches were found in 76% of cases in ICD-10 and in 54% in SNOMED-CT. We conclude that there are sizable gaps in the SNOMED-CT and ICD coding systems for metabolic disorders. There may be similar gaps for other classes of rare and genetic disorders. We have demonstrated that expert groups can help in addressing such coding issues. Our coding system has been made available to the ICD and SNOMED-CT organizations as well as to the Orphanet and HPO organizations for further public application and updates will be published online (www.ddrmd.nl and www.cineas.org).

Seizure control and treatment changes in pregnancy: observations from the EURAP epilepsy pregnancy registry.

PURPOSE: To analyze seizure control, dose adjustments, and other changes of antiepileptic drug (AED) treatment during pregnancy in a large cohort of women with epilepsy entering pregnancy on monotherapy with carbamazepine, lamotrigine, phenobarbital, or valproate. METHODS: Seizure control and AED treatment were recorded prospectively in 3,806 pregnancies of 3,451 women with epilepsy taking part in European and International Registry of Antiepileptic Drugs and Pregnancy (EURAP), an international AED and pregnancy registry. KEY FINDINGS: Of all cases, 66.6% remained seizure-free throughout pregnancy. Generalized tonic-clonic seizures (GTCS) occurred in 15.2% of the pregnancies. Women with idiopathic generalized epilepsies were more likely to remain seizure-free (73.6%) than women with localization-related epilepsy (59.5%; p < 0.0001). Worsening in seizure control from the first to second or third trimesters occurred in 15.8% of pregnancies. The AED dose was increased during pregnancy in 26.0% and a second AED added to the initial monotherapy in 2.6% of all pregnancies. Seizures were more likely to occur in the first trimester in pregnancies with an increased drug load (35%; increased dose and/or addition of another AED) than in pregnancies without an increased drug load (15.3%) (p < 0.0001). Compared with other monotherapies, pregnancies exposed to lamotrigine were less likely to be seizure-free, 58.2% (p < 0.0001); had more GTCS, 21.1% (p < 0.0001); had a greater likelihood of deterioration in seizure control from first to second or third trimesters, 19.9% (p < 0.01), and were more likely to require an increase in drug load, 47.7% (p < 0.0001). The mean dose increases from the first to third trimesters were 26% for lamotrigine, 5% for carbamazepine, 11% for phenobarbital, and 6% for valproate. There were 21 cases of status epilepticus (10 convulsive): none with maternal mortality and only one with a subsequent stillbirth. SIGNIFICANCE: Although the majority of women remain seizure-free throughout pregnancy, our data suggest that a more proactive approach to adjusting the dose of all AEDs in pregnancy should be considered, in particular for those pregnancies with seizures occurring in the first trimester and those exposed to lamotrigine, to reduce the risk of deterioration in seizure control.

The impact of age on lamotrigine and oxcarbazepine kinetics: a historical cohort study.

Age as well as estrogen levels may have an impact on the pharmacokinetics of lamotrigine (LTG) and monohydroxycarbazepine (MHD), the active metabolite of oxcarbazepine (OXC). To assess the effects of age and menopause, we evaluated retrospectively a therapeutic drug-monitoring database. Samples from 507 women and 302 men taking LTG and 464 women and 319 men taking OXC were used to develop a population pharmacokinetic model. Data were analyzed using NONMEM software and were compared with a population pharmacokinetic model based on samples of 1705 women and 1771 men taking carbamazepine (CBZ). Age was a significant factor contributing to pharmacokinetic variability in individuals using LTG, OXC, and CBZ with increasing clearance as a function of bioavailability (Cl/F) over age 18, a maximum Cl/F at 33years (CBZ) and 36 years (LTG and OXC), and a gradual decrease of Cl/F towards older age. We found no effect of perimenopausal age range on LTG and MHD clearance.

Mutations in WNT10A are present in more than half of isolated hypodontia cases.

BACKGROUND: Dental agenesis is the most common, often heritable, developmental anomaly in humans. Mutations in MSX1, PAX9, AXIN2 and the ectodermal dysplasia genes EDA, EDAR and EDARADD have been detected in familial severe tooth agenesis. However, until recently, in the majority of cases (∼90%) the genetic factor could not be identified, implying that other genes must be involved. Recent insights into the role of Wnt10A in tooth development, and the finding of hypodontia in carriers of the autosomal recessive disorder, odontooncychodermal dysplasia, due to mutations in WNT10A (OMIM 257980; OODD), make WNT10A an interesting candidate gene for dental agenesis. METHODS: In a panel of 34 patients with isolated hypodontia, the candidate gene WNT10A and the genes MSX1, PAX9, IRF6 and AXIN2 have been sequenced. The probands all had isolated agenesis of between six and 28 teeth. RESULTS: WNT10A mutations were identified in 56% of the cases with non-syndromic hypodontia. MSX1, PAX9 and AXIN2 mutations were present in 3%, 9% and 3% of the cases, respectively. CONCLUSION: The authors identified WNT10A as a major gene in the aetiology of isolated hypodontia. By including WNT10A in the DNA diagnostics of isolated tooth agenesis, the yield of molecular testing in this condition was significantly increased from 15% to 71%.

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.

Nav 1.1 dysfunction in genetic epilepsy with febrile seizures-plus or Dravet syndrome.

Relatively few SCN1A mutations associated with genetic epilepsy with febrile seizures-plus (GEFS+) and Dravet syndrome (DS) have been functionally characterized. In contrast to GEFS+, many mutations detected in DS patients are predicted to have complete loss of function. However, functional consequences are not immediately apparent for DS missense mutations. Therefore, we performed a biophysical analysis of three SCN1A missense mutations (R865G, R946C and R946H) we detected in six patients with DS. Furthermore, we compared the functionality of the R865G DS mutation with that of a R859H mutation detected in a GEFS+ patient; the two mutations reside in the same voltage sensor domain of Na(v) 1.1. The four mutations were co-expressed with ß1 and ß2 subunits in tsA201 cells, and characterized using the whole-cell patch clamp technique. The two DS mutations, R946C and R946H, were nonfunctional. However, the novel voltage sensor mutants R859H (GEFS+) and R865G (DS) produced sodium current densities similar to those in wild-type channels. Both mutants had negative shifts in the voltage dependence of activation, slower recovery from inactivation, and increased persistent current. Only the GEFS+ mutant exhibited a loss of function in voltage-dependent channel availability. Our results suggest that the R859H mutation causes GEFS+ by a mixture of biophysical defects in Na(v) 1.1 gating. Interestingly, while loss of Na(v) 1.1 function is common in DS, the R865G mutation may cause DS by overall gain-of-function defects.

Adults with a history of possible Dravet syndrome: an illustration of the importance of analysis of the SCN1A gene.

Most patients with Dravet syndrome have de novo mutations in the neuronal voltage-gated sodium channel type 1 (SCN1A) gene. We report on two unrelated fathers with severe childhood epilepsy compatible with a possible diagnosis of Dravet syndrome, who both have a child with Dravet syndrome. Analysis of the SCN1A gene revealed a pathogenic mutation in both children. One father exhibited somatic mosaicism for the mutation detected in his son. A relatively favorable cognitive outcome in patients with Dravet syndrome patients may be explained by somatic mosaicism for the SCN1A mutation in brain tissue. A mild form of Dravet syndrome in adult patients is associated with a high recurrence risk and possibly a more severe epilepsy phenotype in their offspring.

A retrospective population-based study on seizures related to childhood vaccination.

PURPOSE: Cases of severe childhood epilepsies in temporal association with vaccination have great impact on the acceptance of vaccination programs by parents and health care providers. However, little is known about the type and frequency of seizures and epilepsy syndromes following vaccination. This study aims to describe the clinical features of children presenting with seizures after vaccination using a register-based cohort. METHODS: We surveyed the national German database of adverse events following immunization (AEFI) for reported seizures and epilepsies in children aged 0-6 years. All cases reported in 2006-2008 were analyzed retrospectively; available clinical information was reevaluated and classified by seizure type and epilepsy syndrome. KEY FINDINGS: In total, 328 cases reported between 2006 and 2008 were included. Data supportive of seizures or epilepsy were present in 247 (75.3%) of 328 patients with a mean interval between the vaccination and the epileptic event of 24 h and 7.5 days for inactivated and attenuated vaccines, respectively. Fifty-one (15.5%) of 328 patients presented with syncope, hypotonic-hyporesponsive episodes, or other nonepileptic events. Information was insufficient for classification into epileptic versus nonepileptic events in 30 (11.3%) of 328 patients. For cases with confirmed seizures, febrile seizures were present in 121 (49%) of 247 cases, and 38 (15.4%) of 247 patients had single afebrile seizures. Status epilepticus was described in 21 (8.5%) of 247 patients. Thirty-one (12.6%) of 247 patients presented with various pediatric epilepsy syndromes. Severe childhood epilepsies (Dravet syndrome, West syndrome, Lennox-Gastaut syndrome, or Doose syndrome) were diagnosed in 29 (11.7%) of 247 patients, with the vaccination-associated event being the first documented seizure in 15 (51.7%) of 29 patients. SIGNIFICANCE: Vaccination-associated seizures present in the setting of various epilepsy syndromes, including severe childhood epilepsies in >10% of cases. Early diagnosis of the corresponding epilepsy syndromes and confirmation of an underlying etiology is important for treatment decisions, genetic counseling, and public health evaluation of vaccine safety.

Recurrent microdeletions at 15q11.2 and 16p13.11 predispose to idiopathic generalized epilepsies.

Idiopathic generalized epilepsies account for 30% of all epilepsies. Despite a predominant genetic aetiology, the genetic factors predisposing to idiopathic generalized epilepsies remain elusive. Studies of structural genomic variations have revealed a significant excess of recurrent microdeletions at 1q21.1, 15q11.2, 15q13.3, 16p11.2, 16p13.11 and 22q11.2 in various neuropsychiatric disorders including autism, intellectual disability and schizophrenia. Microdeletions at 15q13.3 have recently been shown to constitute a strong genetic risk factor for common idiopathic generalized epilepsy syndromes, implicating that other recurrent microdeletions may also be involved in epileptogenesis. This study aimed to investigate the impact of five microdeletions at the genomic hotspot regions 1q21.1, 15q11.2, 16p11.2, 16p13.11 and 22q11.2 on the genetic risk to common idiopathic generalized epilepsy syndromes. The candidate microdeletions were assessed by high-density single nucleotide polymorphism arrays in 1234 patients with idiopathic generalized epilepsy from North-western Europe and 3022 controls from the German population. Microdeletions were validated by quantitative polymerase chain reaction and their breakpoints refined by array comparative genomic hybridization. In total, 22 patients with idiopathic generalized epilepsy (1.8%) carried one of the five novel microdeletions compared with nine controls (0.3%) (odds ratio = 6.1; 95% confidence interval 2.8-13.2; chi(2) = 26.7; 1 degree of freedom; P = 2.4 x 10(-7)). Microdeletions were observed at 1q21.1 [Idiopathic generalized epilepsy (IGE)/control: 1/1], 15q11.2 (IGE/control: 12/6), 16p11.2 IGE/control: 1/0, 16p13.11 (IGE/control: 6/2) and 22q11.2 (IGE/control: 2/0). Significant associations with IGEs were found for the microdeletions at 15q11.2 (odds ratio = 4.9; 95% confidence interval 1.8-13.2; P = 4.2 x 10(-4)) and 16p13.11 (odds ratio = 7.4; 95% confidence interval 1.3-74.7; P = 0.009). Including nine patients with idiopathic generalized epilepsy in this cohort with known 15q13.3 microdeletions (IGE/control: 9/0), parental transmission could be examined in 14 families. While 10 microdeletions were inherited (seven maternal and three paternal transmissions), four microdeletions occurred de novo at 15q13.3 (n = 1), 16p13.11 (n = 2) and 22q11.2 (n = 1). Eight of the transmitting parents were clinically unaffected, suggesting that the microdeletion itself is not sufficient to cause the epilepsy phenotype. Although the microdeletions investigated are individually rare (<1%) in patients with idiopathic generalized epilepsy, they collectively seem to account for a significant fraction of the genetic variance in common idiopathic generalized epilepsy syndromes. The present results indicate an involvement of microdeletions at 15q11.2 and 16p13.11 in epileptogenesis and strengthen the evidence that recurrent microdeletions at 15q11.2, 15q13.3 and 16p13.11 confer a pleiotropic susceptibility effect to a broad range of neuropsychiatric disorders.

Drug monitoring of lamotrigine and oxcarbazepine combination during pregnancy.

Little is known about pregnancy-induced alterations in the pharmacokinetics of the newer antiepileptic drugs, especially when used in combinations. Two women receiving combination therapy of lamotrigine (LTG) and oxcarbazepine (OXC) were followed prospectively during pregnancy and puerperium. Steady-state concentrations of LTG and the active metabolite of OXC, 10-hydroxycarbazepine (MHD), were measured at regular intervals using a dried blood spot method, and clearances were calculated. A strong effect of pregnancy on the clearance of both LTG and MHD was seen. An increase in seizure frequency occurred in both women. This stresses the importance of therapeutic drug monitoring of LTG and MHD during pregnancy. In case of breakthrough seizures or increased seizure frequency, dosage adjustment of both drugs may be required.