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We identified individuals with variations in ACTL6B, a component of the chromatin remodeling machinery including the BAF complex. Ten individuals harbored bi-allelic mutations and presented with global developmental delay, epileptic encephalopathy, and spasticity, and ten individuals with de novo heterozygous mutations displayed intellectual disability, ambulation deficits, severe language impairment, hypotonia, Rett-like stereotypies, and minor facial dysmorphisms (wide mouth, diastema, bulbous nose). Nine of these ten unrelated individuals had the identical de novo c.1027G>A (p.Gly343Arg) mutation. Human-derived neurons were generated that recaptured ACTL6B expression patterns in development from progenitor cell to post-mitotic neuron, validating the use of this model. Engineered knock-out of ACTL6B in wild-type human neurons resulted in profound deficits in dendrite development, a result recapitulated in two individuals with different bi-allelic mutations, and reversed on clonal genetic repair or exogenous expression of ACTL6B. Whole-transcriptome analyses and whole-genomic profiling of the BAF complex in wild-type and bi-allelic mutant ACTL6B neural progenitor cells and neurons revealed increased genomic binding of the BAF complex in ACTL6B mutants, with corresponding transcriptional changes in several genes including TPPP and FSCN1, suggesting that altered regulation of some cytoskeletal genes contribute to altered dendrite development. Assessment of bi-alleic and heterozygous ACTL6B mutations on an ACTL6B knock-out human background demonstrated that bi-allelic mutations mimic engineered deletion deficits while heterozygous mutations do not, suggesting that the former are loss of function and the latter are gain of function. These results reveal a role for ACTL6B in neurodevelopment and implicate another component of chromatin remodeling machinery in brain disease.

Introduction: Pediatric frontal and temporal lobe epilepsies (FLE, TLE) have been associated with language impairments and structural and functional brain alterations. However, there is no clear consensus regarding the specific patterns of cerebral reorganization of language networks in these patients. The current study aims at characterizing the cerebral language networks in children with FLE or TLE, and the association between brain network characteristics and cognitive abilities. Methods: Twenty (20) children with FLE or TLE aged between 6 and 18 years and 29 age- and sex-matched healthy controls underwent a neuropsychological evaluation and a simultaneous functional near-infrared spectroscopy and electroencephalography (fNIRS-EEG) recording at rest and during a receptive language task. EEG was used to identify potential subclinical seizures in patients. We removed these time intervals from the fNIRS signal to investigate language brain networks and not epileptogenic networks. Functional connectivity matrices on fNIRS oxy-hemoglobin concentration changes were computed using cross-correlations between all channels. Results and discussion: Group comparisons of residual matrices (=individual task-based matrix minus individual resting-state matrix) revealed significantly reduced connectivity within the left and between hemispheres, increased connectivity within the right hemisphere and higher right hemispheric local efficiency for the epilepsy group compared to the control group. The epilepsy group had significantly lower cognitive performance in all domains compared to their healthy peers. Epilepsy patients' local network efficiency in the left hemisphere was negatively associated with the estimated IQ (p = 0.014), suggesting that brain reorganization in response to FLE and TLE does not allow for an optimal cognitive development. [ABSTRACT FROM AUTHOR]

Aim: To evaluate clinicians' and patients' perceptions of pharmacogenetic testing in a clinical setting. Materials & methods: This is a pragmatic mixed-method prospective observational study. Hospital pharmacists and neurologists participated in focus groups regarding pharmacogenetic testing; patients who received pharmacogenetic testing and their community pharmacists completed surveys to assess their perception of these tests. Results: Most study participants had a positive view of pharmacogenetic testing. Three major themes were identified from the focus groups: receptiveness to pharmacogenetic testing, pharmacogenetic test characteristics and integrating pharmacogenetic tests into practice. Conclusion: The views reported are encouraging for the eventual implementation of pharmacogenetics in practice. Local integration of these tests is an essential step to improve patient care through personalized medicine. Genetic tests can help predict patients' response to medication. This study aimed to evaluate clinicians' and patients' perceptions of these genetic tests. Pediatric patients, with epilepsy, were tested and completed a survey to assess their perception of these tests. A survey was also completed by their community pharmacists, and virtual discussion groups were held with hospital pharmacists and neurologists. Most participants had a positive view of these tests, with three major themes identified from the discussion groups: receptiveness to testing, test characteristics and integration of tests into practice. The views reported are encouraging for the eventual implementation of these tests in practice, an essential step to improve patient care through personalized medicine. A pragmatic mixed-methods prospective observational study found that clinicians and patients favor the implementation of pharmacogenetic testing in the field of pediatric epilepsy to improve patient care #pharmacogenetics #pediatric #neurology. [ABSTRACT FROM AUTHOR]

Reye's syndrome is an acute deterioration of brain tissue and brain function accompanied by a fatty degeneration of the liver and other organs. The cause of the disease remains unknown, but the syndrome often follows a viral infection such as influenza (flu), and some research has implicated the use of aspirin in these cases. Several recent studies have suggested that the rate of aspirin use in children and the incidence of Reye's syndrome have declined during the period of 1980 to 1985. At face value these data appear to support a relationship of aspirin use and Reye's syndrome. However, diagnostic practices have changed in the years since Reye's was first described and it is possible that, armed with current medical knowledge, a re-examination of prior cases could result in a re-classification of cases previously diagnosed as Reye's syndrome. Forty-nine cases, in which the patient was discharged or died, diagnosed as Reye's syndrome at one medical center over a 17-year period were reviewed by three clinicians. In 42 of the 49 cases (86 percent) there was agreement in diagnosing the patient's problem. In the remaining cases discussion among the clinicians resulted in the assignment of a diagnosis. The original diagnosis of Reye's syndrome was ranked certain in 1 case, probable in 11, and unlikely or excluded in 36 cases. This suggests that the actual occurrence of Reye's syndrome has always been low in this institution, and that the apparent reduction in the incidence of Reye's syndrome may be an artifact of prior mistaken diagnoses, rather than a result of decreased use of aspirin in treating children with viral infections. (Consumer Summary produced by Reliance Medical Information, Inc.)

CACNA1A loss-of-function mutations classically present as episodic ataxia type 2 (EA2), with brief episodes of ataxia and nystagmus, or with progressive spinocerebellar ataxia (SCA6). A minority of patients carrying CACNA1A mutations develops epilepsy. Non-motor symptoms associated with these mutations are often overlooked. In this study, we report 16 affected individuals from four unrelated families presenting with a spectrum of cognitive impairment including intellectual deficiency, executive dysfunction, ADHD and/or autism, as well as childhood-onset epileptic encephalopathy with refractory absence epilepsy, febrile seizures, downbeat nystagmus and episodic ataxia. Sequencing revealed one CACNA1A gene deletion, two deleterious CACNA1A point mutations including one known stop-gain and one new frameshift variant and a new splice-site variant. This report illustrates the phenotypic heterogeneity of CACNA1A loss-of-function mutations and stresses the cognitive and epileptic manifestations caused by the loss of CaV2.1 channels function, presumably affecting cerebellar, cortical and limbic networks. [ABSTRACT FROM AUTHOR]

Epilepsy is a heterogeneous neurological disease affecting approximately 50 million people worldwide. Genetic factors play an important role in both the onset and severity of the condition, with mutations in several ion‐channel genes being implicated, including those encoding the GABAA receptor. Here, we evaluated the frequency of additional mutations in the GABAA receptor by direct sequencing of the complete open reading frame of the GABRA1 and GABRG2 genes from a cohort of French Canadian families with idiopathic generalized epilepsy (IGE). Using this approach, we have identified three novel mutations that were absent in over 400 control chromosomes. In GABRA1, two mutations were found, with the first being a 25‐bp insertion that was associated with intron retention (i.e. K353delins18X) and the second corresponding to a single point mutation that replaced the aspartate 219 residue with an asparagine (i.e. D219N). Electrophysiological analysis revealed that K353delins18X and D219N altered GABAA receptor function by reducing the total surface expression of mature protein and/or by curtailing neurotransmitter effectiveness. Both defects would be expected to have a detrimental effect on inhibitory control of neuronal circuits. In contrast, the single point mutation identified in the GABRG2 gene, namely P83S, was indistinguishable from the wildtype subunit in terms of surface expression and functionality. This finding was all the more intriguing as the mutation exhibited a high degree of penetrance in three generations of one French Canadian family. Further experimentation will be required to understand how this mutation contributes to the occurrence of IGE in these individuals. [ABSTRACT FROM AUTHOR]

We sequenced genes coding for components of the SNARE complex ( STX1A, VAMP2, SNAP25) and their regulatory proteins (STXBP1/Munc18-1, SYT1), which are essential for neurotransmission, in 95 patients with idiopathic mental retardation. We identified de novo mutations in STXBP1 (nonsense, p.R388X; splicing, c.169+1G>A) in two patients with severe mental retardation and nonsyndromic epilepsy. Reverse transcriptase polymerase chain reaction and sequencing showed that the splicing mutation creates a stop codon downstream of exon-3. No de novo or deleterious mutations in STXBP1 were found in 190 control subjects, or in 142 autistic patients. These results suggest that STXBP1 disruption is associated with autosomal dominant mental retardation and nonsyndromic epilepsy. Ann Neurol 2009;65:748-753 [ABSTRACT FROM AUTHOR]

Seizures are an early sign of brain injury in newborns. These seizures are in most cases repetitive or associated with asymptomatic electrographic seizures. Despite the relative resistance of the immature brain to seizure-induced brain damage, there is more and more evidence that neonatal seizures impair normal brain development. This review addresses the changes associated with neonatal seizures and discusses current and future potential neuroprotective strategies. [Copyright &y& Elsevier]

Summary: Purpose: To assess the influence of the family history (FH) of epilepsy or febrile seizures (FSs) on the clinical presentation of FSs and on their outcome. Methods: We reviewed the charts of 482 children admitted to the Ste-Justine Hospital with FSs between 3 months and 6 years of age and followed for at least 5 years. Results: Children with a positive FH of epilepsy (n=67) showed significantly more focal and recurrent FSs than those without such a FH. The risk of developing partial epilepsy (n=17) or generalized epilepsy (n=19) was significantly greater in children with focal or recurrent FSs, respectively. In children with focal FSs, only two out of 30 (6.7%) children with a negative FH of epilepsy developed partial epilepsy compared with four out of nine (44.4%) children with a positive FH. In children with recurrent FSs, as much as seven out of 34 (20.6%) children with a positive FH of epilepsy developed generalized epilepsy compared to only eight out of 161 (0.05%) of those with a negative FH. Nevertheless, when not taking into account the clinical presentation of FSs, the positive FH of epilepsy constituted a risk factor for developing generalized but not partial epilepsy. Finally, children with a positive FH of FSs (n=120) exhibited significantly more recurrent FSs than those without such a FH, but this did not modify the risk of epilepsy. Conclusion: The FH of FSs and/or epilepsy should be taken into account when evaluating the risk of FSs recurrence and of epilepsy. [Copyright &y& Elsevier]

Although many genes that predispose for epilepsy in humans have been determined, those that underlie the classical syndromes of idiopathic generalized epilepsy (IGE) have yet to be identified. We report that an Ala322Asp mutation in GABRA1, encoding the α1 subunit of the γ-aminobutyric acid receptor subtype A (GABA[sub A]), is found in affected individuals of a large French Canadian family with juvenile myoclonic epilepsy. Compared with wildtype receptors, GABA[sub A] receptors that contain the mutant subunit show a lesser amplitude of GABA-activated currents in vitro, indicating that seizures may result from loss of function of this inhibitory ligand-gated channel. Our results confirm that mutation of GABRA1 predisposes towards a common idiopathic generalized epilepsy syndrome in humans. [ABSTRACT FROM AUTHOR]

STXBP1 (Munc18-1) is a component of the machinery involved in the fusion of secretory vesicles to the presynaptic membrane for the release of neurotransmitters. De novo missense mutations in STXBP1 were recently reported in patients with Ohtahara syndrome, a form of encephalopathy with severe early-onset epilepsy. In addition, sequencing of the coding region of STXBP1 in 95 patients with non-syndromic intellectual disability (NSID) revealed de novo truncating mutations in two patients who also showed severe non-specific epilepsy, suggesting that STXBP1 disruption has the potential of causing a wide spectrum of epileptic disorders in association with intellectual disability. Here, we report on the mutational screening of STXBP1 in a different series of 50 patients with NSID and the identification of a novel de novo truncating mutation (c.1206delT/ p.Y402X) in a male with NSID, but surprisingly with no history of epilepsy. This is the first report of a patient with a truncating mutation in STXBP1 that does not show epilepsy, thus, expanding the clinical spectrum associated with STXBP1 disruption. [ABSTRACT FROM AUTHOR]

Background: Seizures are one of the most common symptoms of pediatric brain tumors. The purpose of this study was to define seizures related to primary central nervous system tumors and to identify risk factors predictive of seizure occurrence and recurrence.Methods: We reviewed the records of children treated from January 1, 2004, to January 1, 2018 and collected data including age, gender, tumor location, histology, extent of initial resection, seizure characteristics, treatment modalities, recurrence, and seizure control. A binomial logistic regression was performed to determine the risk factors of seizure occurrence.Results: During the observation period, 348 children were diagnosed with a primary brain tumor. The median age at diagnosis was 7.8 years, and the median follow-up interval was 3.9 years. There were 196 boys (56.3%). In our cohort, a total of 70 children (20.1%) experienced seizures. Most of them (64.3%) had cortical tumors. All patients with dysembryoplastic neuroepithelial tumors and 81.8% of patients with glioneuronal tumors presented seizures. Risk factors associated with an increased risk for seizures included cortical location, tumor recurrence, and age at diagnosis. Thirty-nine (86.7%) patients with seizures at diagnosis were seizure free at last follow-up (Engel 1). Significantly more patients (69.6%) with a gross total resection were withdrawn from their antiepileptic drugs when compared with those with subtotal resection (27.3%, P = 0.007).Conclusions: Our study is the largest cohort in children with tumor-related seizures and brings new insight in terms of seizure risk according to tumor types and evolution following treatment. [ABSTRACT FROM AUTHOR]

Abstract: Ataxia-telangiectasia is a rare autosomal recessive disorder characterized by progressive cerebellar ataxia, oculocutaneous telangiectasias, and variable degrees of immunodeficiency. Immunologic evaluations of affected patients often reveal anomalies of humoral and cell-mediated immunity. We describe a case of ataxia-telangiectasia with an atypical immunodeficiency and a novel mutation in the ATM gene. The patient presented at age 3 years with a perineal cellulitis associated with profound neutropenia and T-cell lymphopenia. Serum immunoglobulin levels and antibody titers were normal. Neurologic evaluation revealed minimal hypotonia and wide-based gait, without other signs of cerebellar dysfunction. The alpha-fetoprotein level was elevated, and molecular genetic testing confirmed the diagnosis of ataxia-telangiectasia, uncovering a novel ATM gene mutation c.3931C>T (p.Gln1311X) in exon 28. This patient presents a unique immunologic pattern with normal immunoglobulin levels, significant lymphopenia, and profound neutropenia. The diagnosis of ataxia-telangiectasia should be considered in children presenting with gait disorder and immunologic defects, regardless of subtype and severity. [Copyright &y& Elsevier]

Epileptic encephalopathies are increasingly thought to be of genetic origin, although the exact etiology remains uncertain in many cases. We describe here three girls from two nonconsanguineous families affected by a clinical entity characterized by dysmorphic features, early-onset intractable epilepsy, intellectual disability, and cortical blindness. In individuals from each family, brain imaging also showed specific changes, including an abnormally marked pontobulbar sulcus and abnormal signals (T2 hyperintensities) and atrophy in the occipital lobe. Exome sequencing performed in the first family did not reveal any gene with rare homozygous variants shared by both affected siblings. It did, however, show one gene, DOCK7, with two rare heterozygous variants (c.2510delA [p.Asp837Alafs∗48] and c.3709C>T [p.Arg1237∗]) found in both affected sisters. Exome sequencing performed in the proband of the second family also showed the presence of two rare heterozygous variants (c.983C>G [p.Ser328∗] and c.6232G>T [p.Glu2078∗]) in DOCK7. Sanger sequencing confirmed that all three individuals are compound heterozygotes for these truncating mutations in DOCK7. These mutations have not been observed in public SNP databases and are predicted to abolish domains critical for DOCK7 function. DOCK7 codes for a Rac guanine nucleotide exchange factor that has been implicated in the genesis and polarization of newborn pyramidal neurons and in the morphological differentiation of GABAergic interneurons in the developing cortex. All together, these observations suggest that loss of DOCK7 function causes a syndromic form of epileptic encephalopathy by affecting multiple neuronal processes. [Copyright &y& Elsevier]