FAHN/SPG35: a narrow phenotypic spectrum across disease classifications.

The endoplasmic reticulum enzyme fatty acid 2-hydroxylase (FA2H) plays a major role in the formation of 2-hydroxy glycosphingolipids, main components of myelin. FA2H deficiency in mice leads to severe central demyelination and axon loss. In humans it has been associated with phenotypes from the neurodegeneration with brain iron accumulation (fatty acid hydroxylase-associated neurodegeneration, FAHN), hereditary spastic paraplegia (HSP type SPG35) and leukodystrophy (leukodystrophy with spasticity and dystonia) spectrum. We performed an in-depth clinical and retrospective neurophysiological and imaging study in a cohort of 19 cases with biallelic FA2H mutations. FAHN/SPG35 manifests with early childhood onset predominantly lower limb spastic tetraparesis and truncal instability, dysarthria, dysphagia, cerebellar ataxia, and cognitive deficits, often accompanied by exotropia and movement disorders. The disease is rapidly progressive with loss of ambulation after a median of 7 years after disease onset and demonstrates little interindividual variability. The hair of FAHN/SPG35 patients shows a bristle-like appearance; scanning electron microscopy of patient hair shafts reveals deformities (longitudinal grooves) as well as plaque-like adhesions to the hair, likely caused by an abnormal sebum composition also described in a mouse model of FA2H deficiency. Characteristic imaging features of FAHN/SPG35 can be summarized by the 'WHAT' acronym: white matter changes, hypointensity of the globus pallidus, ponto-cerebellar atrophy, and thin corpus callosum. At least three of four imaging features are present in 85% of FA2H mutation carriers. Here, we report the first systematic, large cohort study in FAHN/SPG35 and determine the phenotypic spectrum, define the disease course and identify clinical and imaging biomarkers.

Hereditary spastic paraplegia type 5: natural history, biomarkers and a randomized controlled trial.

Spastic paraplegia type 5 (SPG5) is a rare subtype of hereditary spastic paraplegia, a highly heterogeneous group of neurodegenerative disorders defined by progressive neurodegeneration of the corticospinal tract motor neurons. SPG5 is caused by recessive mutations in the gene CYP7B1 encoding oxysterol-7α-hydroxylase. This enzyme is involved in the degradation of cholesterol into primary bile acids. CYP7B1 deficiency has been shown to lead to accumulation of neurotoxic oxysterols. In this multicentre study, we have performed detailed clinical and biochemical analysis in 34 genetically confirmed SPG5 cases from 28 families, studied dose-dependent neurotoxicity of oxysterols in human cortical neurons and performed a randomized placebo-controlled double blind interventional trial targeting oxysterol accumulation in serum of SPG5 patients. Clinically, SPG5 manifested in childhood or adolescence (median 13 years). Gait ataxia was a common feature. SPG5 patients lost the ability to walk independently after a median disease duration of 23 years and became wheelchair dependent after a median 33 years. The overall cross-sectional progression rate of 0.56 points on the Spastic Paraplegia Rating Scale per year was slightly lower than the longitudinal progression rate of 0.80 points per year. Biochemically, marked accumulation of CYP7B1 substrates including 27-hydroxycholesterol was confirmed in serum (n = 19) and cerebrospinal fluid (n = 17) of SPG5 patients. Moreover, 27-hydroxycholesterol levels in serum correlated with disease severity and disease duration. Oxysterols were found to impair metabolic activity and viability of human cortical neurons at concentrations found in SPG5 patients, indicating that elevated levels of oxysterols might be key pathogenic factors in SPG5. We thus performed a randomized placebo-controlled trial (EudraCT 2015-000978-35) with atorvastatin 40 mg/day for 9 weeks in 14 SPG5 patients with 27-hydroxycholesterol levels in serum as the primary outcome measure. Atorvastatin, but not placebo, reduced serum 27-hydroxycholesterol from 853 ng/ml [interquartile range (IQR) 683-1113] to 641 (IQR 507-694) (-31.5%, P = 0.001, Mann-Whitney U-test). Similarly, 25-hydroxycholesterol levels in serum were reduced. In cerebrospinal fluid 27-hydroxycholesterol was reduced by 8.4% but this did not significantly differ from placebo. As expected, no effects were seen on clinical outcome parameters in this short-term trial. In this study, we define the mutational and phenotypic spectrum of SPG5, examine the correlation of disease severity and progression with oxysterol concentrations, and demonstrate in a randomized controlled trial that atorvastatin treatment can effectively lower 27-hydroxycholesterol levels in serum of SPG5 patients. We thus demonstrate the first causal treatment strategy in hereditary spastic paraplegia.

STUB1/CHIP mutations cause Gordon Holmes syndrome as part of a widespread multisystemic neurodegeneration: evidence from four novel mutations.

BACKGROUND: CHIP, the protein encoded by STUB1, is a central component of cellular protein homeostasis and interacts with several key proteins involved in the pathogenesis of manifold neurodegenerative diseases. This gives rise to the hypothesis that mutations in STUB1 might cause a far more multisystemic neurodegenerative phenotype than the previously reported cerebellar ataxia syndrome. METHODS: Whole exome sequencing data-sets from n = 87 index subjects of two ataxia cohorts were screened for individuals with STUB1 mutations. In-depth phenotyping by clinical evaluation and neuroimaging was performed in mutation carriers. RESULTS: We identified four novel STUB1 mutations in three affected subjects from two index families (frequency 2/87 = 2.3%). All three subjects presented with a severe multisystemic phenotype including severe dementia, spastic tetraparesis, epilepsy, and autonomic dysfunction in addition to cerebellar ataxia, plus hypogonadism in one index patient. Diffusion tensor imaging revealed degeneration of manifold supra- and infratentorial tracts. CONCLUSIONS: Our findings provide clinical and imaging support for the notion that CHIP is a crucial converging point of manifold neurodegenerative processes, corresponding with its universal biological function in neurodegeneration. Further, our data reveal the second STUB1 family with ataxia plus hypogonadism reported so far, demonstrating that Gordon Holmes syndrome is indeed a recurrent manifestation of STUB1. However, it does not present in isolation, but as part of a broad multisystemic neurodegenerative process. This supports the notion that STUB1 disease should be conceptualized not by historical or clinical syndromic names, but as a variable multisystemic disease defined by disturbed function of the underlying STUB1 gene, which translates into a multidimensional gradual spectrum of variably associated clinical signs and symptoms.

TBK1 Mutation Spectrum in an Extended European Patient Cohort with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.

We investigated the mutation spectrum of the TANK-Binding Kinase 1 (TBK1) gene and its associated phenotypic spectrum by exonic resequencing of TBK1 in a cohort of 2,538 patients with frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), or FTD plus ALS, ascertained within the European Early-Onset Dementia Consortium. We assessed pathogenicity of predicted protein-truncating mutations by measuring loss of RNA expression. Functional effect of in-frame amino acid deletions and missense mutations was further explored in vivo on protein level and in vitro by an NFκB-induced luciferase reporter assay and measuring phosphorylated TBK1. The protein-truncating mutations led to the loss of transcript through nonsense-mediated mRNA decay. For the in-frame amino acid deletions, we demonstrated loss of TBK1 or phosphorylated TBK1 protein. An important fraction of the missense mutations compromised NFκB activation indicating that at least some functions of TBK1 are lost. Although missense mutations were also present in controls, over three times more mutations affecting TBK1 functioning were found in the mutation fraction observed in patients only, suggesting high-risk alleles (P = 0.03). Total mutation frequency for confirmed TBK1 LoF mutations in the European cohort was 0.7%, with frequencies in the clinical subgroups of 0.4% in FTD, 1.3% in ALS, and 3.6% in FTD-ALS.

Complicated spastic paraplegia in patients with AP5Z1 mutations (SPG48).

OBJECTIVE: Biallelic mutations in the AP5Z1 gene encoding the AP-5 ζ subunit have been described in a small number of patients with hereditary spastic paraplegia (HSP) (SPG48); we sought to define genotype-phenotype correlations in patients with homozygous or compound heterozygous sequence variants predicted to be deleterious. METHODS: We performed clinical, radiologic, and pathologic studies in 6 patients with biallelic mutations in AP5Z1. RESULTS: In 4 of the 6 patients, there was complete loss of AP-5 ζ protein. Clinical features encompassed not only prominent spastic paraparesis but also sensory and motor neuropathy, ataxia, dystonia, myoclonus, and parkinsonism. Skin fibroblasts from affected patients tested positive for periodic acid Schiff and autofluorescent storage material, while electron microscopic analysis demonstrated lamellar storage material consistent with abnormal storage of lysosomal material. CONCLUSIONS: Our findings expand the spectrum of AP5Z1-associated neurodegenerative disorders and point to clinical and pathophysiologic overlap between autosomal recessive forms of HSP and lysosomal storage disorders.

Automated non-EEG based seizure detection: Do users have a say?

PURPOSE: Quality of life of patients with epilepsy depends largely upon unpredictability of seizure occurrence and would improve by predicting seizures or at least by detecting seizures (after their clinical onset) and react timely. Detection systems are available and researched, but little is known about the actual need and user preferences. The first indicates the market potential; the second allows us to incorporate user requirements into the engineering process. METHODS: We questioned 20 pediatric and young adult patients, 114 caregivers, and 21 involved medical doctors and described, analyzed, and compared their experiences with systems for seizure detection, their opinions on usefulness and purpose of seizure detection, and their requirements for such a device. RESULTS: Experience with detection systems is limited, but 65% of patients and caregivers and 85% of medical doctors express the usefulness, more so during night than day. The need is higher in patients with more severe intellectual disability. The higher the seizure frequency, the higher the need, opinions in the seizure-free group being more divided. Most patients and caregivers require 100% correct detection, and on average, one false alarm per seizure (one per week for those seizure-free) is accepted. Medical doctors allow 90% correct detections and between two false alarms per week and one per month depending on seizure frequency. Detection of seizures involving heavy movement and falls is judged most important by patients and caregivers and second to most by medical doctors. The latter judge heart rate monitoring most relevant, both towards seizure detection and SUDEP (sudden unexpected death in epilepsy) prevention. CONCLUSIONS: The results, including a goal of 90% correct detections and one false alarm per seizure, should be considered in development of seizure detectors.

A detailed clinical analysis of 13 patients with AUTS2 syndrome further delineates the phenotypic spectrum and underscores the behavioural phenotype.

BACKGROUND: AUTS2 syndrome is an 'intellectual disability (ID) syndrome' caused by genomic rearrangements, deletions, intragenic duplications or mutations disrupting AUTS2. So far, 50 patients with AUTS2 syndrome have been described, but clinical data are limited and almost all cases involved young children. METHODS: We present a detailed clinical description of 13 patients (including six adults) with AUTS2 syndrome who have a pathogenic mutation or deletion in AUTS2. All patients were systematically evaluated by the same clinical geneticist. RESULTS: All patients have borderline to severe ID/developmental delay, 83-100% have microcephaly and feeding difficulties. Congenital malformations are rare, but mild heart defects, contractures and genital malformations do occur. There are no major health issues in the adults; the oldest of whom is now 59 years of age. Behaviour is marked by it is a friendly outgoing social interaction. Specific features of autism (like obsessive behaviour) are seen frequently (83%), but classical autism was not diagnosed in any. A mild clinical phenotype is associated with a small in-frame 5' deletions, which are often inherited. Deletions and other mutations causing haploinsufficiency of the full-length AUTS2 transcript give a more severe phenotype and occur de novo. CONCLUSIONS: The 13 patients with AUTS2 syndrome with unique pathogenic deletions scattered around the AUTS2 locus confirm a phenotype-genotype correlation. Despite individual variations, AUTS2 syndrome emerges as a specific ID syndrome with microcephaly, feeding difficulties, dysmorphic features and a specific behavioural phenotype.

SYNE1 ataxia is a common recessive ataxia with major non-cerebellar features: a large multi-centre study.

Mutations in the synaptic nuclear envelope protein 1 (SYNE1) gene have been reported to cause a relatively pure, slowly progressive cerebellar recessive ataxia mostly identified in Quebec, Canada. Combining next-generation sequencing techniques and deep-phenotyping (clinics, magnetic resonance imaging, positron emission tomography, muscle histology), we here established the frequency, phenotypic spectrum and genetic spectrum of SYNE1 in a screening of 434 non-Canadian index patients from seven centres across Europe. Patients were screened by whole-exome sequencing or targeted panel sequencing, yielding 23 unrelated families with recessive truncating SYNE1 mutations (23/434 = 5.3%). In these families, 35 different mutations were identified, 34 of them not previously linked to human disease. While only 5/26 patients (19%) showed the classical SYNE1 phenotype of mildly progressive pure cerebellar ataxia, 21/26 (81%) exhibited additional complicating features, including motor neuron features in 15/26 (58%). In three patients, respiratory dysfunction was part of an early-onset multisystemic neuromuscular phenotype with mental retardation, leading to premature death at age 36 years in one of them. Positron emission tomography imaging confirmed hypometabolism in extra-cerebellar regions such as the brainstem. Muscle biopsy reliably showed severely reduced or absent SYNE1 staining, indicating its potential use as a non-genetic indicator for underlying SYNE1 mutations. Our findings, which present the largest systematic series of SYNE1 patients and mutations outside Canada, revise the view that SYNE1 ataxia causes mainly a relatively pure cerebellar recessive ataxia and that it is largely limited to Quebec. Instead, complex phenotypes with a wide range of extra-cerebellar neurological and non-neurological dysfunctions are frequent, including in particular motor neuron and brainstem dysfunction. The disease course in this multisystemic neurodegenerative disease can be fatal, including premature death due to respiratory dysfunction. With a relative frequency of ∼5%, SYNE1 is one of the more common recessive ataxias worldwide.

Motor neuron degeneration in spastic paraplegia 11 mimics amyotrophic lateral sclerosis lesions.

The most common form of autosomal recessive hereditary spastic paraplegia is caused by mutations in the SPG11/KIAA1840 gene on chromosome 15q. The nature of the vast majority of SPG11 mutations found to date suggests a loss-of-function mechanism of the encoded protein, spatacsin. The SPG11 phenotype is, in most cases, characterized by a progressive spasticity with neuropathy, cognitive impairment and a thin corpus callosum on brain MRI. Full neuropathological characterization has not been reported to date despite the description of >100 SPG11 mutations. We describe here the clinical and pathological features observed in two unrelated females, members of genetically ascertained SPG11 families originating from Belgium and Italy, respectively. We confirm the presence of lesions of motor tracts in medulla oblongata and spinal cord associated with other lesions of the central nervous system. Interestingly, we report for the first time pathological hallmarks of SPG11 in neurons that include intracytoplasmic granular lysosome-like structures mainly in supratentorial areas, and others in subtentorial areas that are partially reminiscent of those observed in amyotrophic lateral sclerosis, such as ubiquitin and p62 aggregates, except that they are never labelled with anti-TDP-43 or anti-cystatin C. The neuropathological overlap with amyotrophic lateral sclerosis, associated with some shared clinical manifestations, opens up new fields of investigation in the physiopathological continuum of motor neuron degeneration.

The spectrum of epilepsy caused by POLG mutations.

Mutations in POLG are increasingly recognized as a cause of refractory occipital lobe epilepsy (OLE) and status epilepticus (SE). Our aim was to describe the epilepsy syndrome in seven patients with POLG mutations. We retrospectively reviewed the medical records of seven patients with POLG mutations and epilepsy. Mutation analysis was performed by direct sequencing of the coding exons of the POLG gene. Disease onset was at a median age of 18 years (range 12-26). Epilepsy was the presenting problem in six patients. All had focal seizures, with motor (n = 6) and visual (n = 6) phenomena. Six patients had secondarily generalized seizures and two patients had myoclonic seizures. Six patients had one or more episodes of refractory SE, including focal (n = 5), subtle (n = 4), myoclonic (n = 2) and convulsive (n = 3) SE. During or after SE, brain MRI showed lesions affecting the occipital lobe in all patients, probably due to continuous epileptic activity. Five of the six patients with SE died during treatment of SE, one due to valproate-induced hepatotoxicity. Associated clinical symptoms were ataxia (n = 6), polyneuropathy (n = 6), progressive external ophthalmoplegia (PEO) (n = 3) and migraine (n = 3). Epilepsy may be the first and dominant neurological problem caused by POLG mutations. The epilepsy may be severe and the condition of the patient may end in fatal SE. Refractory OLE and SE in a patient with polyneuropathy, ataxia, PEO or migraine warrant screening for POLG mutations. In this clinical setting, valproate should not be given in view of the risk of fatal hepatotoxicity.

First de novo KCND3 mutation causes severe Kv4.3 channel dysfunction leading to early onset cerebellar ataxia, intellectual disability, oral apraxia and epilepsy.

BACKGROUND: Identification of the first de novo mutation in potassium voltage-gated channel, shal-related subfamily, member 3 (KCND3) in a patient with complex early onset cerebellar ataxia in order to expand the genetic and phenotypic spectrum. METHODS: Whole exome sequencing in a cerebellar ataxia patient and subsequent immunocytochemistry, immunoblotting and patch clamp assays of the channel were performed. RESULTS: A de novo KCND3 mutation (c.877_885dupCGCGTCTTC; p.Arg293_Phe295dup) was found duplicating the RVF motif and thereby adding an extra positive charge to voltage-gated potassium 4.3 (Kv4.3) in the voltage-sensor domain causing a severe shift of the voltage-dependence gating to more depolarized voltages. The patient displayed a severe phenotype with early onset cerebellar ataxia complicated by intellectual disability, epilepsy, attention deficit hyperactivity disorder, strabismus, oral apraxia and joint hyperlaxity. CONCLUSIONS: We identified a de novo KCND3 mutation causing the most marked change in Kv4.3's channel properties reported so far, which correlated with a severe and unique spinocerebellar ataxia (SCA) type 19/22 disease phenotype.

Rare mutations in SQSTM1 modify susceptibility to frontotemporal lobar degeneration.

Mutations in the gene coding for Sequestosome 1 (SQSTM1) have been genetically associated with amyotrophic lateral sclerosis (ALS) and Paget disease of bone. In the present study, we analyzed the SQSTM1 coding sequence for mutations in an extended cohort of 1,808 patients with frontotemporal lobar degeneration (FTLD), ascertained within the European Early-Onset Dementia consortium. As control dataset, we sequenced 1,625 European control individuals and analyzed whole-exome sequence data of 2,274 German individuals (total n = 3,899). Association of rare SQSTM1 mutations was calculated in a meta-analysis of 4,332 FTLD and 10,240 control alleles. We identified 25 coding variants in FTLD patients of which 10 have not been described. Fifteen mutations were absent in the control individuals (carrier frequency <0.00026) whilst the others were rare in both patients and control individuals. When pooling all variants with a minor allele frequency <0.01, an overall frequency of 3.2 % was calculated in patients. Rare variant association analysis between patients and controls showed no difference over the whole protein, but suggested that rare mutations clustering in the UBA domain of SQSTM1 may influence disease susceptibility by doubling the risk for FTLD (RR = 2.18 [95 % CI 1.24-3.85]; corrected p value = 0.042). Detailed histopathology demonstrated that mutations in SQSTM1 associate with widespread neuronal and glial phospho-TDP-43 pathology. With this study, we provide further evidence for a putative role of rare mutations in SQSTM1 in the genetic etiology of FTLD and showed that, comparable to other FTLD/ALS genes, SQSTM1 mutations are associated with TDP-43 pathology.

Partial deletion of AFG3L2 causing spinocerebellar ataxia type 28.

OBJECTIVE: To identify the genetic cause of autosomal dominant spinocerebellar ataxia type 28 (SCA28) with ptosis in 2 Belgian families without AFG3L2 point mutations and further extend the clinical spectrum of SCA28 through the study of a brain autopsy, advanced MRI, and cell-based functional assays exploring the underlying disease mechanism. METHODS: Two large families were clinically examined in detail. Linkage analysis and multiplex amplicon quantification were performed. A brain autopsy was obtained. Brain MRI with voxel-based morphometry and diffusion tensor imaging was performed. RNA and Western blot analysis and blue native-polyacrylamide gel electrophoresis experiments were performed. RESULTS: MRI analysis demonstrated a significant cerebellar atrophy, as well as white matter degeneration in the cerebellar peduncles, corticospinal tracts, corpus callosum, and cingulum. A brain autopsy showed severe atrophy of the upper part of the cerebellar hemisphere. Ubiquitin and p62 immunoreactive intranuclear inclusions were found in cerebral and cerebellar cortical neurons, in neurons of the hippocampus, and in pontine and medullary nuclei. An identical heterozygous partial deletion of exons 14 to 16 of the AFG3L2 gene was found in both families. Additional functional assays in patient-derived cell lines revealed haploinsufficiency as the underlying disease mechanism. CONCLUSIONS: Our study expands the phenotypic characterization of SCA28 by means of brain pathology and diffusion tensor imaging/voxel-based morphometry MRIs. The identification of a partial AFG3L2 deletion and the subsequent functional studies reveal loss of function as the most likely disease mechanism. Specific testing for deletions in AFG3L2 is warranted because these escape standard sequencing.

PRRT2 mutations: exploring the phenotypical boundaries.

BACKGROUND: Mutations in the proline-rich transmembrane protein 2 (PRRT2) gene have been identified in patients with benign (familial) infantile convulsions (B(F)IC), infantile convulsions with choreoathetosis (ICCA) and paroxysmal dyskinesias (PDs). However it remains unknown whether PRRT2 mutations are causal in other epilepsy syndromes. After we discovered a PRRT2 mutation in a large family with ICCA containing one individual with febrile seizures (FS) and one individual with West syndrome, we analysed PRRT2 in a heterogeneous cohort of patients with different types of infantile epilepsy. METHODS: We screened a cohort of 460 patients with B(F)IC or ICCA, fever related seizures or infantile epileptic encephalopathies. All patients were tested for point mutations using direct sequencing. RESULTS: We identified heterozygous mutations in 16 individuals: 10 familial and 6 sporadic cases. All patients were diagnosed with B(F)IC, ICCA or PD. We were not able to detect mutations in any of the other epilepsy syndromes. Several mutation carriers had learning disabilities and/or impaired fine motor skills later in life. CONCLUSIONS: PRRT2 mutations do not seem to be involved in the aetiology of FS or infantile epileptic encephalopathies. Therefore B(F)IC, ICCA and PD remain the core phenotypes associated with PRRT2 mutations. The presence of learning disabilities or neuropsychiatric problems in several mutation carriers calls for additional clinical studies addressing this developmental aspect in more detail.

First line management of prolonged convulsive seizures in children and adults: good practice points.

Over the past decades, it has become clear that the most efficient way to prevent status epilepticus is to stop the seizure as fast as possible, and early treatment of prolonged convulsive seizures has become an integral part of the overall treatment strategy in epilepsy. Benzodiazepines are the first choice drugs to be used as emergency medication. This treatment in the early phases of a seizure often implies a 'pre-medical' setting before intervention of medically trained persons. In this paper, we propose "good practice points" for first line management of prolonged convulsive seizures in children and adults in a 'pre-medical' setting.

Loss of function of glucocerebrosidase GBA2 is responsible for motor neuron defects in hereditary spastic paraplegia.

Spastic paraplegia 46 refers to a locus mapped to chromosome 9 that accounts for a complicated autosomal-recessive form of hereditary spastic paraplegia (HSP). With next-generation sequencing in three independent families, we identified four different mutations in GBA2 (three truncating variants and one missense variant), which were found to cosegregate with the disease and were absent in controls. GBA2 encodes a microsomal nonlysosomal glucosylceramidase that catalyzes the conversion of glucosylceramide to free glucose and ceramide and the hydrolysis of bile acid 3-O-glucosides. The missense variant was also found at the homozygous state in a simplex subject in whom no residual glucocerebrosidase activity of GBA2 could be evidenced in blood cells, opening the way to a possible measurement of this enzyme activity in clinical practice. The overall phenotype was a complex HSP with mental impairment, cataract, and hypogonadism in males associated with various degrees of corpus callosum and cerebellar atrophy on brain imaging. Antisense morpholino oligonucleotides targeting the zebrafish GBA2 orthologous gene led to abnormal motor behavior and axonal shortening/branching of motoneurons that were rescued by the human wild-type mRNA but not by applying the same mRNA containing the missense mutation. This study highlights the role of ceramide metabolism in HSP pathology.

Recommendations for the treatment of epilepsy in adult patients in general practice in Belgium: an update.

In 2008, a group of Belgian epilepsy experts published recommendations for antiepileptic drug (AED) treatment of epilepsies in adults and children. Selection of compounds was based on the registration and reimbursement status in Belgium, the level of evidence for efficacy, common daily practice and the personal views and experiences of the authors. In November 2011 the validity of these recommendations was reviewed by the same group of Belgian epilepsy experts who contributed to the preparation of the original paper. The recommendations made in 2008 for initial monotherapy in paediatric patients were still considered to be valid, except for the first choice treatment for childhood absence epilepsy. This update therefore focuses on the treatment recommendations for initial monotherapy and add-on treatment in adult patients. Several other relevant aspects of treatment with AEDs are addressed, including considerations for optimal combination of AEDs (rational polytherapy), pharmacokinetic properties, pharmacodynamic and pharmacokinetic interaction profile, adverse effects, comorbidity, treatment of elderly patients, AED treatment during pregnancy, and generic substitution of AEDs.

KCNQ2 encephalopathy: emerging phenotype of a neonatal epileptic encephalopathy.

OBJECTIVE: KCNQ2 and KCNQ3 mutations are known to be responsible for benign familial neonatal seizures (BFNS). A few reports on patients with a KCNQ2 mutation with a more severe outcome exist, but a definite relationship has not been established. In this study we investigated whether KCNQ2/3 mutations are a frequent cause of epileptic encephalopathies with an early onset and whether a recognizable phenotype exists. METHODS: We analyzed 80 patients with unexplained neonatal or early-infantile seizures and associated psychomotor retardation for KCNQ2 and KCNQ3 mutations. Clinical and imaging data were reviewed in detail. RESULTS: We found 7 different heterozygous KCNQ2 mutations in 8 patients (8/80; 10%); 6 mutations arose de novo. One parent with a milder phenotype was mosaic for the mutation. No KCNQ3 mutations were found. The 8 patients had onset of intractable seizures in the first week of life with a prominent tonic component. Seizures generally resolved by age 3 years but the children had profound, or less frequently severe, intellectual disability with motor impairment. Electroencephalography (EEG) at onset showed a burst-suppression pattern or multifocal epileptiform activity. Early magnetic resonance imaging (MRI) of the brain showed characteristic hyperintensities in the basal ganglia and thalamus that later resolved. INTERPRETATION: KCNQ2 mutations are found in a substantial proportion of patients with a neonatal epileptic encephalopathy with a potentially recognizable electroclinical and radiological phenotype. This suggests that KCNQ2 screening should be included in the diagnostic workup of refractory neonatal seizures of unknown origin.

The SCN1A variant database: a novel research and diagnostic tool.

The neuronal voltage-gated sodium channel Na(v)1.1 encoded by the SCN1A gene plays an important role in the generation and propagation of action potentials in the central nervous system. Altered function of this channel due to mutations in SCN1A leads to hypersynchronous neuronal discharges resulting in seizures or migrainous attaques. A large number of distinct sequence variants in SCN1A are associated with diverse epilepsy and migraine syndromes. We developed an online and freely available database containing all reported sequence variants in SCN1A (http://www.molgen.ua.ac.be/SCN1AMutations/). We verified 623 distinct sequence variants, listed them using standard nomenclature for description and classified them according to their putative pathogenic nature. We provided links to relevant publications and information on the associated phenotype. The database can be queried using cDNA or protein position, phenotype, variant type or publication. By listing all SCN1A variants in a comprehensive manner, this database will facilitate interpretation of newly identified sequence variants and provide better insight into the genotype-phenotype relations of the growing number of SCN1A mutations.