ORCID Profile
0000-0002-5021-415X
Current Organisations
University of Glasgow
,
University of Dundee
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Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 06-2021
Publisher: Springer Science and Business Media LLC
Date: 20-07-2023
DOI: 10.1038/S41467-023-39539-6
Abstract: Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 in iduals with seizure disorders, 16,109 in iduals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 in iduals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of in iduals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between in idual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice.
Publisher: Wiley
Date: 26-10-2006
DOI: 10.1002/AJMG.A.31443
Abstract: Several brain malformations have been described in rare patients with the deletion 22q11.2 syndrome (DEL22q11) including agenesis of the corpus callosum, pachygyria or polymicrogyria (PMG), cerebellar anomalies and meningomyelocele, with PMG reported most frequently. In view of our interest in the causes of PMG, we reviewed clinical data including brain-imaging studies on 21 patients with PMG associated with deletion 22q11.2 and another 11 from the literature. We found that the cortical malformation consists of perisylvian PMG of variable severity and frequent asymmetry with a striking predisposition for the right hemisphere (P = 0.008). This and other observations suggest that the PMG may be a sequela of abnormal embryonic vascular development rather than a primary brain malformation. We also noted mild cerebellar hypoplasia or mega-cisterna magna in 8 of 24 patients. Although this was not the focus of the present study, mild cerebellar anomalies are probably the most common brain malformation associated with DEL22q11.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 22-08-2012
Publisher: American Medical Association (AMA)
Date: 26-02-2010
Publisher: Springer Science and Business Media LLC
Date: 29-10-2019
DOI: 10.1038/S41467-019-12671-Y
Abstract: Familial Adult Myoclonic Epilepsy (FAME) is characterised by cortical myoclonic tremor usually from the second decade of life and overt myoclonic or generalised tonic-clonic seizures. Four independent loci have been implicated in FAME on chromosomes (chr) 2, 3, 5 and 8. Using whole genome sequencing and repeat primed PCR, we provide evidence that chr2-linked FAME (FAME2) is caused by an expansion of an ATTTC pentamer within the first intron of STARD7 . The ATTTC expansions segregate in 158/158 in iduals typically affected by FAME from 22 pedigrees including 16 previously reported families recruited worldwide. RNA sequencing from patient derived fibroblasts shows no accumulation of the AUUUU or AUUUC repeat sequences and STARD7 gene expression is not affected. These data, in combination with other genes bearing similar mutations that have been implicated in FAME, suggest ATTTC expansions may cause this disorder, irrespective of the genomic locus involved.
Publisher: Springer Science and Business Media LLC
Date: 07-2016
DOI: 10.1007/S00439-016-1700-8
Abstract: Familial adult myoclonus epilepsy (FAME) is a rare autosomal dominant disorder characterized by adult onset, involuntary muscle jerks, cortical myoclonus and occasional seizures. FAME is genetically heterogeneous with more than 70 families reported worldwide and five potential disease loci. The efforts to identify potential causal variants have been unsuccessful in all but three families. To date, linkage analysis has been the main approach to find and narrow FAME critical regions. We propose an alternative method, pedigree free identity-by-descent (IBD) mapping, that infers regions of the genome between in iduals that have been inherited from a common ancestor. IBD mapping provides an alternative to linkage analysis in the presence of allelic and locus heterogeneity by detecting clusters of in iduals who share a common allele. Succeeding IBD mapping, gene prioritization based on gene co-expression analysis can be used to identify the most promising candidate genes. We performed an IBD analysis using high-density single nucleotide polymorphism (SNP) array data followed by gene prioritization on a FAME cohort of ten European families and one Australian/New Zealander family eight of which had known disease loci. By identifying IBD regions common to multiple families, we were able to narrow the FAME2 locus to a 9.78 megabase interval within 2p11.2-q11.2. We provide additional evidence of a founder effect in four Italian families and allelic heterogeneity with at least four distinct founders responsible for FAME at the FAME2 locus. In addition, we suggest candidate disease genes using gene prioritization based on gene co-expression analysis.
Publisher: Wiley
Date: 09-11-2022
DOI: 10.1111/EPI.17431
Abstract: This study was undertaken to evaluate the long-term safety and effectiveness of fenfluramine in patients with Lennox-Gastaut syndrome (LGS). Eligible patients with LGS who completed a 14-week phase 3 randomized clinical trial enrolled in an open-label extension (OLE NCT03355209). All patients were initially started on .2 mg/kg/day fenfluramine and after 1 month were titrated by effectiveness and tolerability, which were assessed at 3-month intervals. The protocol-specified treatment duration was 12 months, but COVID-19-related delays resulted in 142 patients completing their final visit after 12 months. As of October 19, 2020, 247 patients were enrolled in the OLE. Mean age was 14.3 ± 7.6 years (79 [32%] adults) and median fenfluramine treatment duration was 364 days 88.3% of patients received 2-4 concomitant antiseizure medications. Median percentage change in monthly drop seizure frequency was -28.6% over the entire OLE (n = 241) and -50.5% at Month 15 (n = 142, p .0001) 75 of 241 patients (31.1%) experienced ≥50% reduction in drop seizure frequency. Median percentage change in nondrop seizure frequency was -45.9% (n = 192, p = .0038). Generalized tonic-clonic seizures (GTCS) and tonic seizures were most responsive to treatment, with median reductions over the entire OLE of 48.8% (p .0001, n = 106) and 35.8% (p .0001, n = 186), respectively. A total of 37.6% (95% confidence interval [CI] = 31.4%-44.1%, n = 237) of investigators and 35.2% of caregivers (95% CI = 29.1%-41.8%, n = 230) rated patients as Much Improved/Very Much Improved on the Clinical Global Impression of Improvement scale. The most frequent treatment-emergent adverse events were decreased appetite (16.2%) and fatigue (13.4%). No cases of valvular heart disease (VHD) or pulmonary arterial hypertension (PAH) were observed. Patients with LGS experienced sustained reductions in drop seizure frequency on fenfluramine treatment, with a particularly robust reduction in frequency of GTCS, the key risk factor for sudden unexpected death in epilepsy. Fenfluramine was generally well tolerated VHD or PAH was not observed long-term. Fenfluramine may provide an important long-term treatment option for LGS.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.CELREP.2018.11.029
Abstract: The mammalian neocortex has undergone remarkable changes through evolution. A consequence of such rapid evolutionary events could be a trade-off that has rendered the brain susceptible to certain neurodevelopmental and neuropsychiatric conditions. We analyzed the exomes of 65 patients with the structural brain malformation periventricular nodular heterotopia (PH). De novo coding variants were observed in excess in genes defining a transcriptomic signature of basal radial glia, a cell type linked to brain evolution. In addition, we located two variants in human isoforms of two genes that have no ortholog in mice. Modulating the levels of one of these isoforms for the gene PLEKHG6 demonstrated its role in regulating neuroprogenitor differentiation and neuronal migration via RhoA, with phenotypic recapitulation of PH in human cerebral organoids. This suggests that this PLEKHG6 isoform is an ex le of a primate-specific genomic element supporting brain development.
Publisher: Wiley
Date: 19-11-2019
DOI: 10.1002/ANA.25619
Publisher: Elsevier BV
Date: 05-2016
Publisher: Wiley
Date: 04-2011
DOI: 10.1111/J.1528-1167.2011.02997.X
Abstract: Dravet syndrome (DS), otherwise known as severe myoclonic epilepsy of infancy (SMEI), is an epileptic encephalopathy presenting in the first year of life. DS has a genetic etiology: between 70% and 80% of patients carry sodium channel α1 subunit gene (SCN1A) abnormalities, and truncating mutations account for about 40% and have a significant correlation with an earlier age of seizures onset. The remaining SCN1A mutations comprise splice-site and missense mutations, most of which fall into the pore-forming region of the sodium channel. Mutations are randomly distributed across the SCN1A protein. Most mutations are de novo, but familial SCN1A mutations also occur. Somatic mosaic mutations have also been reported in some patients and might explain the phenotypical variability seen in some familial cases. SCN1A exons deletions or chromosomal rearrangements involving SCN1A and contiguous genes are also detectable in about 2-3% of patients. A small percentage of female patients with a DS-like phenotype might carry PCDH19 mutations. Rare mutations have been identified in the GABARG2 and SCN1B genes. The etiology of about 20% of DS patients remains unknown, and additional genes are likely to be implicated.
Publisher: Oxford University Press (OUP)
Date: 03-04-2023
Abstract: Dravet syndrome is an archetypal rare severe epilepsy, considered ‘monogenic’, typically caused by loss-of-function SCN1A variants. Despite a recognizable core phenotype, its marked phenotypic heterogeneity is incompletely explained by differences in the causal SCN1A variant or clinical factors. In 34 adults with SCN1A-related Dravet syndrome, we show additional genomic variation beyond SCN1A contributes to phenotype and its ersity, with an excess of rare variants in epilepsy-related genes as a set and ex les of blended phenotypes, including one in idual with an ultra-rare DEPDC5 variant and focal cortical dysplasia. The polygenic risk score for intelligence was lower, and for longevity, higher, in Dravet syndrome than in epilepsy controls. The causal, major-effect, SCN1A variant may need to act against a broadly compromised genomic background to generate the full Dravet syndrome phenotype, whilst genomic resilience may help to ameliorate the risk of premature mortality in adult Dravet syndrome survivors.
Publisher: Wiley
Date: 13-01-2012
DOI: 10.1111/J.1528-1167.2011.03379.X
Abstract: 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. 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. 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). 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.
Publisher: Wiley
Date: 14-04-2016
DOI: 10.1002/MGG3.217
Publisher: Hindawi Limited
Date: 04-10-2019
DOI: 10.1002/HUMU.23915
Abstract: Developmental and epileptic encephalopathies (DEE) refer to a heterogeneous group of devastating neurodevelopmental disorders. Variants in KCNB1 have been recently reported in patients with early-onset DEE. KCNB1 encodes the α subunit of the delayed rectifier voltage-dependent potassium channel K
Publisher: Oxford University Press (OUP)
Date: 05-2021
Abstract: Constitutional heterozygous mutations of ATP1A2 and ATP1A3, encoding for two distinct isoforms of the Na+/K+-ATPase (NKA) alpha-subunit, have been associated with familial hemiplegic migraine (ATP1A2), alternating hemiplegia of childhood (ATP1A2/A3), rapid-onset dystonia-parkinsonism, cerebellar ataxia-areflexia-progressive optic atrophy, and relapsing encephalopathy with cerebellar ataxia (all ATP1A3). A few reports have described single in iduals with heterozygous mutations of ATP1A2/A3 associated with severe childhood epilepsies. Early lethal hydrops fetalis, arthrogryposis, microcephaly, and polymicrogyria have been associated with homozygous truncating mutations in ATP1A2. We investigated the genetic causes of developmental and epileptic encephalopathies variably associated with malformations of cortical development in a large cohort and identified 22 patients with de novo or inherited heterozygous ATP1A2/A3 mutations. We characterized clinical, neuroimaging and neuropathological findings, performed in silico and in vitro assays of the mutations’ effects on the NKA-pump function, and studied genotype-phenotype correlations. Twenty-two patients harboured 19 distinct heterozygous mutations of ATP1A2 (six patients, five mutations) and ATP1A3 (16 patients, 14 mutations, including a mosaic in idual). Polymicrogyria occurred in 10 (45%) patients, showing a mainly bilateral perisylvian pattern. Most patients manifested early, often neonatal, onset seizures with a multifocal or migrating pattern. A distinctive, ‘profound’ phenotype, featuring polymicrogyria or progressive brain atrophy and epilepsy, resulted in early lethality in seven patients (32%). In silico evaluation predicted all mutations to be detrimental. We tested 14 mutations in transfected COS-1 cells and demonstrated impaired NKA-pump activity, consistent with severe loss of function. Genotype-phenotype analysis suggested a link between the most severe phenotypes and lack of COS-1 cell survival, and also revealed a wide continuum of severity distributed across mutations that variably impair NKA-pump activity. We performed neuropathological analysis of the whole brain in two in iduals with polymicrogyria respectively related to a heterozygous ATP1A3 mutation and a homozygous ATP1A2 mutation and found close similarities with findings suggesting a mainly neural pathogenesis, compounded by vascular and leptomeningeal abnormalities. Combining our report with other studies, we estimate that ∼5% of mutations in ATP1A2 and 12% in ATP1A3 can be associated with the severe and novel phenotypes that we describe here. Notably, a few of these mutations were associated with more than one phenotype. These findings assign novel, ‘profound’ and early lethal phenotypes of developmental and epileptic encephalopathies and polymicrogyria to the phenotypic spectrum associated with heterozygous ATP1A2/A3 mutations and indicate that severely impaired NKA pump function can disrupt brain morphogenesis.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 19-07-2022
DOI: 10.1212/WNL.0000000000200715
Abstract: Pathogenic STXBP1 variants cause a severe early-onset developmental and epileptic encephalopathy (STXBP1-DEE). We aimed to investigate the natural history of STXBP1-DEE in adults focusing on seizure evolution, the presence of movement disorders, and the level of functional (in)dependence. In this observational study, patients with a minimum age of 18 years carrying a (likely) pathogenic STXBP1 variant were recruited through medical genetics departments and epilepsy centers. Treating clinicians completed clinical questionnaires and performed semistructured video examinations while performing tasks from the (modified) Unified Parkinson Disease Rating Scale when possible. Thirty adult patients were included for summary statistics, with video recordings available for 19 patients. The median age at last follow-up was 24 years (range 18–58 years). All patients had epilepsy, with a median onset age of 3.5 months. At last follow-up, 80% of adults had treatment-resistant seizures despite long periods of seizure freedom in 37%. Tonic-clonic, focal, and tonic seizures were most frequent in adults. Epileptic spasms, an unusual feature beyond infancy, were present in 3 adults. All in iduals had developmental impairment. Periods of regression were present in 59% and did not always correlate with flare-ups in seizure activity. Eighty-seven percent had severe or profound intellectual disability, 42% had autistic features, and 65% had significant behavioral problems. Video examinations showed gait disorders in all 12 patients able to walk, including postural abnormalities with external rotation of the feet, broad-based gait, and asymmetric posture/dystonia. Tremor, present in 56%, was predominantly of the intention/action type. Stereotypies were seen in 63%. Functional outcome concerning mobility was variable ranging from independent walking (50%) to wheelchair dependence (39%). Seventy-one percent of adults were nonverbal, and all were dependent on caregivers for most activities of daily living. STXBP1-DEE warrants continuous monitoring for seizures in adult life. Periods of regression are more frequent than previously established and can occur into adulthood. Movement disorders are often present and involve multiple systems. Although functional mobility is variable in adulthood, STXBP1-DEE frequently leads to severe cognitive impairments and a high level of functional dependence. Understanding the natural history of STXBP1-DEE is important for prognostication and will inform future therapeutic trials.
Publisher: American Medical Association (AMA)
Date: 06-2022
Publisher: Elsevier BV
Date: 08-2023
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-12-2018
DOI: 10.1212/WNL.0000000000006729
Abstract: To delineate the epileptology, a key part of the SYNGAP1 phenotypic spectrum, in a large patient cohort. Patients were recruited via investigators' practices or social media. We included patients with (likely) pathogenic SYNGAP1 variants or chromosome 6p21.32 microdeletions incorporating SYNGAP1 . We analyzed patients' phenotypes using a standardized epilepsy questionnaire, medical records, EEG, MRI, and seizure videos. We included 57 patients (53% male, median age 8 years) with SYNGAP1 mutations (n = 53) or microdeletions (n = 4). Of the 57 patients, 56 had epilepsy: generalized in 55, with focal seizures in 7 and infantile spasms in 1. Median seizure onset age was 2 years. A novel type of drop attack was identified comprising eyelid myoclonia evolving to a myoclonic-atonic (n = 5) or atonic (n = 8) seizure. Seizure types included eyelid myoclonia with absences (65%), myoclonic seizures (34%), atypical (20%) and typical (18%) absences, and atonic seizures (14%), triggered by eating in 25%. Developmental delay preceded seizure onset in 54 of 56 (96%) patients for whom early developmental history was available. Developmental plateauing or regression occurred with seizures in 56 in the context of a developmental and epileptic encephalopathy (DEE). Fifty-five of 57 patients had intellectual disability, which was moderate to severe in 50. Other common features included behavioral problems (73%) high pain threshold (72%) eating problems, including oral aversion (68%) hypotonia (67%) sleeping problems (62%) autism spectrum disorder (54%) and ataxia or gait abnormalities (51%). SYNGAP1 mutations cause a generalized DEE with a distinctive syndrome combining epilepsy with eyelid myoclonia with absences and myoclonic-atonic seizures, as well as a predilection to seizures triggered by eating.
Publisher: Wiley
Date: 03-07-2015
DOI: 10.1002/ACN3.224
Publisher: Wiley
Date: 16-04-2015
DOI: 10.1111/EPI.12984
Abstract: To describe the antiepileptic drug (AED) treatment of patients with early infantile epileptic encephalopathy due to KCNQ2 mutations during the neonatal phase and the first year of life. We identified 15 patients and reviewed the electroclinical, neuroimaging, and AED treatment data. Seizure onset was between 1 and 4 days of age with daily tonic asymmetric, focal and clonic seizures in nine patients and status epilepticus in the remaining six. Electroencephalography (EEG) showed multifocal epileptiform abnormalities in nine patients and a burst-suppression pattern in six. All patients were trialed with adequate daily doses of several AEDs before they reached seizure freedom. Six patients (40%) achieved seizure control within 2 weeks of carbamazepine (CBZ) administration and five (33%) were seizure-free with phenytoin (PHT). The last four patients (27%) were successfully treated with topiramate (TPM) (two patients), levetiracetam (LEV) (one), and a combination of LEV with TPM (one). Most patients reached seizure freedom within the first year of life and remained seizure-free thereafter. Twelve patients had moderate-to-severe developmental delay at follow-up. However, the two patients whose seizures ceased within a few days of onset showed only mild cognitive impairment. Our findings suggest that drugs acting on sodium channels including CBZ and PHT should be considered as first-line treatment in patients with KCNQ2 encephalopathy. Voltage-gated sodium and potassium channels co-localize at the neuronal membrane. Therefore, the efficacy of drugs acting as sodium-channel blockers could be linked to their modulating effect on both channels. The type of KCNQ2 mutation might influence AED response as well as developmental outcome. Early recognition of KCNQ2 encephalopathy followed by the most appropriate and effective treatment may be important for reducing the neurodevelopmental impairment associated with this disorder.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-06-2022
Abstract: The centrosome provides an intracellular anchor for the cytoskeleton, regulating cell ision, cell migration, and cilia formation. We used spatial proteomics to elucidate protein interaction networks at the centrosome of human induced pluripotent stem cell–derived neural stem cells (NSCs) and neurons. Centrosome-associated proteins were largely cell type–specific, with protein hubs involved in RNA dynamics. Analysis of neurodevelopmental disease cohorts identified a significant overrepresentation of NSC centrosome proteins with variants in patients with periventricular heterotopia (PH). Expressing the PH-associated mutant pre-mRNA-processing factor 6 (PRPF6) reproduced the periventricular misplacement in the developing mouse brain, highlighting missplicing of transcripts of a microtubule-associated kinase with centrosomal location as essential for the phenotype. Collectively, cell type–specific centrosome interactomes explain how genetic variants in ubiquitous proteins may convey brain-specific phenotypes.
Publisher: Wiley
Date: 24-09-2010
DOI: 10.1111/J.1528-1167.2010.02712.X
Abstract: Early onset absence epilepsy (EOAE) starting before the age of 4 years constitutes a rare subgroup of the idiopathic generalized epilepsies (IGEs). A strong genetic component in IGE has been suggested by twin and family studies. We describe a boy with absence seizures starting at the age of 9 months whose parents both had childhood absence epilepsy. A 192-kb duplication in 1q21.3 was identified in the proband and his father, encompassing the gene CHRNB2 coding for the β-2 subunit of the nicotinic acetylcholine receptor and the gene ADAR coding for adenosine deaminase, an enzyme responsible for RNA editing. Both are candidate genes for seizure disorders. The duplication was not identified in 191 independent IGE patients (93 EOAE 98 classical IGE) or in 1,157 population controls.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Rockefeller University Press
Date: 08-07-2020
DOI: 10.1084/JEM.20192040
Abstract: The exocyst, an octameric protein complex, is an essential component of the membrane transport machinery required for tethering and fusion of vesicles at the plasma membrane. We report pathogenic variants in an exocyst subunit, EXOC2 (Sec5). Affected in iduals have severe developmental delay, dysmorphism, and brain abnormalities variability associated with epilepsy and poor motor skills. Family 1 had two offspring with a homozygous truncating variant in EXOC2 that leads to nonsense-mediated decay of EXOC2 transcript, a severe reduction in exocytosis and vesicle fusion, and undetectable levels of EXOC2 protein. The patient from Family 2 had a milder clinical phenotype and reduced exocytosis. Cells from both patients showed defective Arl13b localization to the primary cilium. The discovery of mutations that partially disable exocyst function provides valuable insight into this essential protein complex in neural development. Since EXOC2 and other exocyst complex subunits are critical to neuronal function, our findings suggest that EXOC2 variants are the cause of the patients’ neurological disorders.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2017
DOI: 10.1038/NG.3761
Publisher: Public Library of Science (PLoS)
Date: 08-05-2018
Publisher: American Medical Association (AMA)
Date: 09-2011
DOI: 10.1001/ARCHNEUROL.2011.102
Abstract: To determine if a significant proportion of patients with myoclonic-astatic epilepsy (MAE) have glucose transporter 1 (GLUT1) deficiency. Genetic analysis. Ambulatory and hospitalized care. Eighty-four unrelated probands with MAE were phenotyped and SLC2A1 was sequenced and analyzed by multiplex ligation-dependent probe lification. Any identified mutations were then screened in controls. Any SLC2A1 mutations. Four of 84 probands with MAE had a mutation of SLC2A1 on sequencing. Multiplex ligation-dependent probe lification analysis did not reveal any genomic rearrangements in 75 of the remaining cases 5 could not be tested. Two patients with MAE with SLC2A1 mutations also developed paroxysmal exertional dyskinesia in childhood. Five percent of our patients with MAE had SLC2A1 mutations, suggesting that patients with MAE should be tested for GLUT1 deficiency. Diagnosis of GLUT1 deficiency is a strong indication for early use of the ketogenic diet, which may substantially improve outcome of this severe disorder.
Publisher: Springer Science and Business Media LLC
Date: 29-10-2019
DOI: 10.1038/S41467-019-12763-9
Abstract: Familial Adult Myoclonic Epilepsy (FAME) is a genetically heterogeneous disorder characterized by cortical tremor and seizures. Intronic TTTTA/TTTCA repeat expansions in SAMD12 (FAME1) are the main cause of FAME in Asia. Using genome sequencing and repeat-primed PCR, we identify another site of this repeat expansion, in MARCH6 (FAME3) in four European families. Analysis of single DNA molecules with nanopore sequencing and molecular combing show that expansions range from 3.3 to 14 kb on average. However, we observe considerable variability in expansion length and structure, supporting the existence of multiple expansion configurations in blood cells and fibroblasts of the same in idual. Moreover, the largest expansions are associated with micro-rearrangements occurring near the expansion in 20% of cells. This study provides further evidence that FAME is caused by intronic TTTTA/TTTCA expansions in distinct genes and reveals that expansions exhibit an unexpectedly high somatic instability that can ultimately result in genomic rearrangements.
Publisher: Springer Science and Business Media LLC
Date: 21-06-2018
DOI: 10.1038/S41467-018-04365-8
Abstract: GWAS have identified risk loci for Inflammatory Bowel Disease (IBD). The majority of disease associations are known to be driven by regulatory variants. To identify the putative causative genes that are perturbed by these variants, we generate a large transcriptome data set (nine disease-relevant cell types) and identify 23,650 cis -eQTL. We show that these are determined by ∼9720 regulatory modules, of which ∼3000 operate in multiple tissues and ∼970 on multiple genes. We identify regulatory modules that drive the disease association for 63 of the 200 risk loci, and show that these are enriched in multigenic modules. Based on these analyses, we resequence 45 of the corresponding 100 candidate genes in 6600 Crohn disease (CD) cases and 5500 controls, and show with burden tests that they include likely causative genes. Our analyses indicate that ≥10-fold larger s le sizes will be required to demonstrate the causality of in idual genes using this approach.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 15-03-2022
DOI: 10.1212/WNL.0000000000200028
Abstract: Pathogenic variants in the neuronal sodium channel α1 subunit gene ( SCN1A ) are the most frequent monogenic cause of epilepsy. Phenotypes comprise a wide clinical spectrum, including severe childhood epilepsy Dravet syndrome, characterized by drug-resistant seizures, intellectual disability, and high mortality and the milder genetic epilepsy with febrile seizures plus (GEFS+), characterized by normal cognition. Early recognition of a child's risk for developing Dravet syndrome vs GEFS+ is key for implementing disease-modifying therapies when available before cognitive impairment emerges. Our objective was to develop and validate a prediction model using clinical and genetic biomarkers for early diagnosis of SCN1A -related epilepsies. We performed a retrospective multicenter cohort study comprising data from patients with SCN1A -positive Dravet syndrome and patients with GEFS+ consecutively referred for genetic testing (March 2001–June 2020) including age at seizure onset and a newly developed SCN1A genetic score. A training cohort was used to develop multiple prediction models that were validated using 2 independent blinded cohorts. Primary outcome was the discriminative accuracy of the model predicting Dravet syndrome vs other GEFS+ phenotypes. A total of 1,018 participants were included. The frequency of Dravet syndrome was 616/743 (83%) in the training cohort, 147/203 (72%) in validation cohort 1, and 60/72 (83%) in validation cohort 2. A high SCN1A genetic score (133.4 [SD 78.5] vs 52.0 [SD 57.5] p 0.001) and young age at onset (6.0 [SD 3.0] vs 14.8 [SD 11.8] months p 0.001) were each associated with Dravet syndrome vs GEFS+. A combined SCN1A genetic score and seizure onset model separated Dravet syndrome from GEFS+ more effectively (area under the curve [AUC] 0.89 [95% CI 0.86–0.92]) and outperformed all other models (AUC 0.79–0.85 p 0.001). Model performance was replicated in both validation cohorts 1 (AUC 0.94 [95% CI 0.91–0.97]) and 2 (AUC 0.92 [95% CI 0.82–1.00]). The prediction model allows objective estimation at disease onset whether a child will develop Dravet syndrome vs GEFS+, assisting clinicians with prognostic counseling and decisions on early institution of precision therapies (scn1a-prediction-model.broadinstitute.org/). This study provides Class II evidence that a combined SCN1A genetic score and seizure onset model distinguishes Dravet syndrome from other GEFS+ phenotypes.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 18-03-2021
DOI: 10.1212/NXG.0000000000000579
Abstract: To describe the phenotypic spectrum in patients with MBD5-associated neurodevelopmental disorder (MAND) and seizures features of MAND include intellectual disability, epilepsy, psychiatric features of aggression and hyperactivity, and dysmorphic features including short stature and microcephaly, sleep disturbance, and ataxia. We performed phenotyping on patients with MBD5 deletions, duplications, or point mutations and a history of seizures. Twenty-three patients with MAND and seizures were included. Median seizure onset age was 2.9 years (range 3 days–13 years). The most common seizure type was generalized tonic-clonic focal, atypical absence, tonic, drop attacks, and myoclonic seizures occurred frequently. Seven children had convulsive status epilepticus and 3 nonconvulsive status epilepticus. Fever, viral illnesses, and hot weather provoked seizures. EEG studies in 17/21 patients were abnormal, typically showing slow generalized spike-wave and background slowing. Nine had drug-resistant epilepsy, although 3 eventually became seizure-free. All but one had moderate-to-severe developmental impairment. Epilepsy syndromes included Lennox-Gastaut syndrome, myoclonic-atonic epilepsy, and infantile spasms syndrome. Behavioral problems in 20/23 included aggression, self-injurious behavior, and sleep disturbance. MBD5 disruption may be associated with severe early childhood-onset developmental and epileptic encephalopathy. Because neuropsychiatric dysfunction is common and severe, it should be an important focus of clinical management.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 31-08-2018
DOI: 10.1212/WNL.0000000000006199
Abstract: To delineate the electroclinical features of SCN8A infantile developmental and epileptic encephalopathy (EIEE13, OMIM #614558). Twenty-two patients, aged 19 months to 22 years, underwent electroclinical assessment. Sixteen of 22 patients had mildly delayed development since birth. Drug-resistant epilepsy started at a median age of 4 months, followed by developmental slowing, pyramidal/extrapyramidal signs (22/22), movement disorders (12/22), cortical blindness (17/22), sialorrhea, and severe gastrointestinal symptoms (15/22), worsening during early childhood and plateauing at age 5 to 9 years. Death occurred in 4 children, following extreme neurologic deterioration, at 22 months to 5.5 years. Nonconvulsive status epilepticus recurred in 14 of 22 patients. The most effective antiepileptic drugs were oxcarbazepine, carbamazepine, phenytoin, and benzodiazepines. EEG showed background deterioration, epileptiform abnormalities with a temporo-occipital predominance, and posterior delta/beta activity correlating with visual impairment. Video-EEG documented focal seizures (FS) (22/22), spasm-like episodes (8/22), cortical myoclonus (8/22), and myoclonic absences (1/22). FS typically clustered and were prolonged ( minutes) with (1) cyanosis, hypomotor, and vegetative semiology, sometimes unnoticed, followed by (2) tonic-vibratory and (3) (hemi)-clonic manifestations ± evolution to a bilateral tonic-clonic seizure. FS had posterior-temporal/occipital onset, slowly spreading and sometimes migrating between hemispheres. Brain MRI showed progressive parenchymal atrophy and restriction of the optic radiations. SCN8A developmental and epileptic encephalopathy has strikingly consistent electroclinical features, suggesting a global progressive brain dysfunction primarily affecting the temporo-occipital regions. Both uncontrolled epilepsy and developmental compromise contribute to the profound impairment (increasing risk of death) during early childhood, but stabilization occurs in late childhood.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Wiley
Date: 21-09-2020
DOI: 10.1111/EPI.16679
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 04-2020
Publisher: Springer Science and Business Media LLC
Date: 17-05-2017
DOI: 10.1038/EJHG.2017.61
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-10-2012
Publisher: Springer Science and Business Media LLC
Date: 09-03-2015
DOI: 10.1038/NG.3239
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 10-2021
Publisher: Wiley
Date: 04-03-2019
DOI: 10.1111/DMCN.14186
Abstract: To assess the relevance and generalizability across countries of concepts of the impact of Dravet syndrome beyond seizures, as recognized by families. Caregivers of children with Dravet syndrome in four countries (Australia [n=8] USA, UK, and Italy [all n=4]) participated in 1-hour qualitative telephone interviews, identifying key Dravet syndrome concepts. Interviews were recorded, transcribed, and, where necessary, translated into English for thematic analysis. Conceptual saturation was assessed and findings compared to the previously developed French conceptual disease model. The most common seizure types reported by caregivers were tonic-clonic, absence, or focal-impaired awareness (localized artial). Fever and physical activity were the most commonly reported triggers. Patient-relevant impacts included impairment in cognition, motor skills, communication, social skills, and behavioural functioning. Caregivers consistently reported negative social, physical, and family impacts. Concepts identified in the interviews showed similarity with the French conceptual model. Minor differences between countries are likely to reflect variations in health care systems. Findings in Italy, Australia, UK, and USA confirm that the key impacts of Dravet syndrome on children and caregivers identified in France are generalizable across countries. Key symptom and impact concepts relevant to children and parents should be targeted as critical outcomes in new therapy evaluations. Relevance of the impact of Dravet syndrome on children and caregivers was confirmed across countries. Patient and caregiver-relevant Dravet syndrome impacts contribute to poorer health-related quality of life. Indirect seizure impacts were reported to be as important as direct impacts. Country-specific differences in concepts probably reflect differences in health care systems.
Publisher: Cold Spring Harbor Laboratory
Date: 24-11-2022
DOI: 10.1101/2022.11.22.22282283
Abstract: By converting physical forces into electrical signals or triggering intracellular cascades, stretch-activated ion channels (SACs) allow the cell to respond to osmotic and mechanical stress. Knowledge of the pathophysiological mechanisms underlying associations of SACs with human disease is limited. Here we describe 16 unrelated patients, with severe early onset developmental and epileptic encephalopathy (DEE), intellectual disability, and severe motor and cortical visual impairment, associated with progressive neurodegenerative brain changes, carrying ten distinct de novo variants of TMEM63B , encoding for a highly conserved SAC. Variants were missense, including the recurrent V44M in 7/16 patients, or in-frame, and affected conserved residues located in transmembrane regions of the protein. In 12 patients, haematological abnormalities co-occurred, such as macrocytosis and haemolysis, requiring blood transfusions in some. We modelled V44M, R443H, and T481N in transfected Neuro2a cells and demonstrated leak inward cation currents across the mutated channel even in isotonic conditions, while the response to hypo-osmotic challenge was impaired, as were the Ca 2+ transients generated under hypo-osmotic stimulation. Ectopic expression of the V44M and G580C variants in Drosophila resulted in early death. TMEM63B -associated DEE represents a novel clinicopathological entity in which altered cation conductivity results in a severe neurological phenotype with progressive brain damage and early onset epilepsy, associated with haematological abnormalities in most patients.
Publisher: Elsevier BV
Date: 03-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 15-04-2016
Publisher: Wiley
Date: 09-2009
DOI: 10.1002/ANA.21724
Abstract: Absence epilepsies of childhood are heterogeneous with most cases following complex inheritance. Those cases with onset before 4 years of age represent a poorly studied subset. We screened 34 patients with early-onset absence epilepsy for mutations in SLC2A1, the gene encoding the GLUT1 glucose transporter. Mutations leading to reduced protein function were found in 12% (4/34) of patients. Two mutations arose de novo, and two were familial. These findings suggest GLUT1 deficiency underlies a significant proportion of early-onset absence epilepsy, which has both genetic counseling and treatment implications because the ketogenic diet is effective in GLUT1 deficiency.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 2017
Publisher: Wiley
Date: 18-05-2021
DOI: 10.1111/EPI.16922
Abstract: Paroxysmal epileptiform abnormalities on electroencephalography (EEG) are the hallmark of epilepsies, but it is uncertain to what extent epilepsy and background EEG oscillations share neurobiological underpinnings. Here, we aimed to assess the genetic correlation between epilepsy and background EEG oscillations. Confounding factors, including the heterogeneous etiology of epilepsies and medication effects, h er studies on background brain activity in people with epilepsy. To overcome this limitation, we compared genetic data from a genome‐wide association study (GWAS) on epilepsy ( n = 12 803 people with epilepsy and 24 218 controls) with that from a GWAS on background EEG ( n = 8425 subjects without epilepsy), in which background EEG oscillation power was quantified in four different frequency bands: alpha, beta, delta, and theta. We replicated our findings in an independent epilepsy replication dataset ( n = 4851 people with epilepsy and 20 428 controls). To assess the genetic overlap between these phenotypes, we performed genetic correlation analyses using linkage disequilibrium score regression, polygenic risk scores, and Mendelian randomization analyses. Our analyses show strong genetic correlations of genetic generalized epilepsy (GGE) with background EEG oscillations, primarily in the beta frequency band. Furthermore, we show that subjects with higher beta and theta polygenic risk scores have a significantly higher risk of having generalized epilepsy. Mendelian randomization analyses suggest a causal effect of GGE genetic liability on beta oscillations. Our results point to shared biological mechanisms underlying background EEG oscillations and the susceptibility for GGE, opening avenues to investigate the clinical utility of background EEG oscillations in the diagnostic workup of epilepsy.
Publisher: Oxford University Press (OUP)
Date: 29-06-2015
DOI: 10.1093/HMG/DDV245
Abstract: Protocadherin 19 (PCDH19) female limited epilepsy (PCDH19-FE also known as epilepsy and mental retardation limited to females, EFMR MIM300088) is an infantile onset epilepsy syndrome with or without intellectual disability (ID) and autism. We investigated transcriptomes of PCDH19-FE female and control primary skin fibroblasts, which are endowed to metabolize neurosteroid hormones. We identified a set of 94 significantly dysregulated genes in PCDH19-FE females. Intriguingly, 43 of the 94 genes (45.7%) showed gender-biased expression enrichment of such genes was highly significant (P = 2.51E-47, two-tailed Fisher exact test). We further investigated the AKR1C1-3 genes, which encode crucial steroid hormone-metabolizing enzymes whose key products include allopregnanolone and estradiol. Both mRNA and protein levels of AKR1C3 were significantly decreased in PCDH19-FE patients. In agreement with this, the blood levels of allopregnanolone were also (P < 0.01) reduced. In conclusion, we show that the deficiency of neurosteroid allopregnanolone, one of the most potent GABA receptor modulators, may contribute to PCDH19-FE. Overall our findings provide evidence for a role of neurosteroids in epilepsy, ID and autism and create realistic opportunities for targeted therapeutic interventions.
Publisher: BMJ
Date: 17-03-2016
DOI: 10.1136/JMEDGENET-2015-103451
Abstract: We aimed to delineate the neurodevelopmental spectrum associated with SYNGAP1 mutations and to investigate genotype-phenotype correlations. We sequenced the exome or screened the exons of SYNGAP1 in a total of 251 patients with neurodevelopmental disorders. Molecular and clinical data from patients with SYNGAP1 mutations from other centres were also collected, focusing on developmental aspects and the associated epilepsy phenotype. A review of SYNGAP1 mutations published in the literature was also performed. We describe 17 unrelated affected in iduals carrying 13 different novel loss-of-function SYNGAP1 mutations. Developmental delay was the first manifestation of SYNGAP1-related encephalopathy intellectual disability became progressively obvious and was associated with autistic behaviours in eight patients. Hypotonia and unstable gait were frequent associated neurological features. With the exception of one patient who experienced a single seizure, all patients had epilepsy, characterised by falls or head drops due to atonic or myoclonic seizures, (myoclonic) absences and/or eyelid myoclonia. Triggers of seizures were frequent (n=7). Seizures were pharmacoresistant in half of the patients. The severity of the epilepsy did not correlate with the presence of autistic features or with the severity of cognitive impairment. Mutations were distributed throughout the gene, but spared spliced 3' and 5' exons. Seizures in patients with mutations in exons 4-5 were more pharmacoresponsive than in patients with mutations in exons 8-15. SYNGAP1 encephalopathy is characterised by early neurodevelopmental delay typically preceding the onset of a relatively recognisable epilepsy comprising generalised seizures (absences, myoclonic jerks) and frequent triggers.
Publisher: Wiley
Date: 17-08-2023
DOI: 10.1111/EPI.17737
Abstract: This study was undertaken to assess the safety and efficacy of fenfluramine in the treatment of convulsive seizures in patients with Dravet syndrome. This multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group, phase 3 clinical trial enrolled patients with Dravet syndrome, aged 2–18 years with poorly controlled convulsive seizures, provided they were not also receiving stiripentol. Eligible patients who had ≥6 convulsive seizures during the 6‐week baseline period were randomized to placebo, fenfluramine .2 mg/kg/day, or fenfluramine .7 mg/kg/day (1:1:1 ratio) administered orally (maximum dose = 26 mg/day). Doses were titrated over 2 weeks and maintained for an additional 12 weeks. The primary endpoint was a comparison of the monthly convulsive seizure frequency (MCSF) during baseline and during the combined titration–maintenance period in patients given fenfluramine .7 mg/kg/day versus patients given placebo. A total of 169 patients were screened, and 143 were randomized to treatment. Mean age was 9.3 ± 4.7 years (±SD), 51% were male, and median baseline MCSF in the three groups ranged 12.7–18.0 per 28 days. Patients treated with fenfluramine .7 mg/kg/day demonstrated a 64.8% (95% confidence interval = 51.8%–74.2%) greater reduction in MCSF compared with placebo ( p .0001). Following fenfluramine .7 mg/kg/day, 72.9% of patients had a ≥50% reduction in MCSF compared with 6.3% in the placebo group ( p .0001). The median longest seizure‐free interval was 30 days in the fenfluramine .7 mg/kg/day group compared with 10 days in the placebo group ( p .0001). The most common adverse events ( % in any group) were decreased appetite, somnolence, pyrexia, and decreased blood glucose. All occurred in higher frequency in fenfluramine groups than placebo. No evidence of valvular heart disease or pulmonary artery hypertension was detected. The results of this third phase 3 clinical trial provide further evidence of the magnitude and durability of the antiseizure response of fenfluramine in children with Dravet syndrome.
Publisher: Springer Science and Business Media LLC
Date: 17-07-2019
DOI: 10.1038/S41598-019-46649-Z
Abstract: Crohn Disease (CD) is a complex genetic disorder for which more than 140 genes have been identified using genome wide association studies (GWAS). However, the genetic architecture of the trait remains largely unknown. The recent development of machine learning (ML) approaches incited us to apply them to classify healthy and diseased people according to their genomic information. The Immunochip dataset containing 18,227 CD patients and 34,050 healthy controls enrolled and genotyped by the international Inflammatory Bowel Disease genetic consortium (IIBDGC) has been re-analyzed using a set of ML methods: penalized logistic regression (LR), gradient boosted trees (GBT) and artificial neural networks (NN). The main score used to compare the methods was the Area Under the ROC Curve (AUC) statistics. The impact of quality control (QC), imputing and coding methods on LR results showed that QC methods and imputation of missing genotypes may artificially increase the scores. At the opposite, neither the patient/control ratio nor marker preselection or coding strategies significantly affected the results. LR methods, including Lasso, Ridge and ElasticNet provided similar results with a maximum AUC of 0.80. GBT methods like XGBoost, LightGBM and CatBoost, together with dense NN with one or more hidden layers, provided similar AUC values, suggesting limited epistatic effects in the genetic architecture of the trait. ML methods detected near all the genetic variants previously identified by GWAS among the best predictors plus additional predictors with lower effects. The robustness and complementarity of the different methods are also studied. Compared to LR, non-linear models such as GBT or NN may provide robust complementary approaches to identify and classify genetic markers.
Publisher: Public Library of Science (PLoS)
Date: 29-11-2017
Publisher: Springer Science and Business Media LLC
Date: 04-2010
DOI: 10.1038/NATURE08979
Publisher: Elsevier BV
Date: 12-2018
Publisher: Oxford University Press (OUP)
Date: 19-04-2010
DOI: 10.1093/BRAIN/AWQ078
Publisher: Elsevier BV
Date: 11-2018
Publisher: Oxford University Press (OUP)
Date: 22-06-2020
Abstract: Cytogenic testing is routinely applied in most neurological centres for severe paediatric epilepsies. However, which characteristics of copy number variants (CNVs) confer most epilepsy risk and which epilepsy subtypes carry the most CNV burden, have not been explored on a genome-wide scale. Here, we present the largest CNV investigation in epilepsy to date with 10 712 European epilepsy cases and 6746 ancestry-matched controls. Patients with genetic generalized epilepsy, lesional focal epilepsy, non-acquired focal epilepsy, and developmental and epileptic encephalopathy were included. All s les were processed with the same technology and analysis pipeline. All investigated epilepsy types, including lesional focal epilepsy patients, showed an increase in CNV burden in at least one tested category compared to controls. However, we observed striking differences in CNV burden across epilepsy types and investigated CNV categories. Genetic generalized epilepsy patients have the highest CNV burden in all categories tested, followed by developmental and epileptic encephalopathy patients. Both epilepsy types also show association for deletions covering genes intolerant for truncating variants. Genome-wide CNV breakpoint association showed not only significant loci for genetic generalized and developmental and epileptic encephalopathy patients but also for lesional focal epilepsy patients. With a 34-fold risk for developing genetic generalized epilepsy, we show for the first time that the established epilepsy-associated 15q13.3 deletion represents the strongest risk CNV for genetic generalized epilepsy across the whole genome. Using the human interactome, we examined the largest connected component of the genes overlapped by CNVs in the four epilepsy types. We observed that genetic generalized epilepsy and non-acquired focal epilepsy formed disease modules. In summary, we show that in all common epilepsy types, 1.5–3% of patients carry epilepsy-associated CNVs. The characteristics of risk CNVs vary tremendously across and within epilepsy types. Thus, we advocate genome-wide genomic testing to identify all disease-associated types of CNVs.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Craig Mowat.