Publications by authors named "Ingrid E Scheffer"

416 Publications

Severe speech impairment is a distinguishing feature of FOXP1-related disorder.

Dev Med Child Neurol 2021 Jun 9. Epub 2021 Jun 9.

Murdoch Children's Research Institute, Parkville, VIC, Australia.

Aim: To delineate the speech and language phenotype of a cohort of individuals with FOXP1-related disorder.

Method: We administered a standardized test battery to examine speech and oral motor function, receptive and expressive language, non-verbal cognition, and adaptive behaviour. Clinical history and cognitive assessments were analysed together with speech and language findings.

Results: Twenty-nine patients (17 females, 12 males; mean age 9y 6mo; median age 8y [range 2y 7mo-33y]; SD 6y 5mo) with pathogenic FOXP1 variants (14 truncating, three missense, three splice site, one in-frame deletion, eight cytogenic deletions; 28 out of 29 were de novo variants) were studied. All had atypical speech, with 21 being verbal and eight minimally verbal. All verbal patients had dysarthric and apraxic features, with phonological deficits in most (14 out of 16). Language scores were low overall. In the 21 individuals who carried truncating or splice site variants and small deletions, expressive abilities were relatively preserved compared with comprehension.

Interpretation: FOXP1-related disorder is characterized by a complex speech and language phenotype with prominent dysarthria, broader motor planning and programming deficits, and linguistic-based phonological errors. Diagnosis of the speech phenotype associated with FOXP1-related dysfunction will inform early targeted therapy.
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http://dx.doi.org/10.1111/dmcn.14955DOI Listing
June 2021

Integrated in silico and experimental assessment of disease relevance of PCDH19 missense variants.

Hum Mutat 2021 Jun 3. Epub 2021 Jun 3.

Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.

PCDH19 is a nonclustered protocadherin molecule involved in axon bundling, synapse function, and transcriptional coregulation. Pathogenic variants in PCDH19 cause infantile-onset epilepsy known as PCDH19-clustering epilepsy or PCDH19-CE. Recent advances in DNA-sequencing technologies have led to a significant increase in the number of reported PCDH19-CE variants, many of uncertain significance. We aimed to determine the best approaches for assessing the disease relevance of missense variants in PCDH19. The application of the American College of Medical Genetics and Association for Molecular Pathology (ACMG-AMP) guidelines was only 50% accurate. Using a training set of 322 known benign or pathogenic missense variants, we identified MutPred2, MutationAssessor, and GPP as the best performing in silico tools. We generated a protein structural model of the extracellular domain and assessed 24 missense variants. We also assessed 24 variants using an in vitro reporter assay. A combination of these tools was 93% accurate in assessing known pathogenic and benign PCDH19 variants. We increased the accuracy of the ACMG-AMP classification of 45 PCDH19 variants from 50% to 94%, using these tools. In summary, we have developed a robust toolbox for the assessment of PCDH19 variant pathogenicity to improve the accuracy of PCDH19-CE variant classification.
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http://dx.doi.org/10.1002/humu.24237DOI Listing
June 2021

Association of Missense Variants With Genetic Epilepsy With Febrile Seizures Plus.

Neurology 2021 05 23;96(18):e2251-e2260. Epub 2021 Mar 23.

From the Adelaide Medical School, Faculty of Health and Medical Sciences (S.E.H., A.E.G., M.A.C., J.G.), and Robinson Research Institute (J.G.), The University of Adelaide; Epilepsy Research Centre, Department of Medicine (B.M.R., R.V.H., M.C., B.E.G., M.F.B., S.P., M.S.H., I.E.S., S.F.B.), Austin Health, University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research; Department of Medical Biology (M.F.B., M.B.), University of Melbourne, Parkville, Australia; Division of Neurology (K.L.H.), Children's Hospital of Philadelphia; Department of Neurology (M.R.S.), Thomas Jefferson University, Philadelphia, PA; Department of Neurology (S.H.), Montefiore Medical Center, Albert Einstein College of Medicine, New York, NY; Institute of Neurology and Neurosurgery at Saint Barnabas (E.B.G.), Livingston, NJ; Department of Neurology (P.W.-W.), Beaumont Hospital, Dublin, Ireland; Royal Brisbane and Women's Hospital (J.T.P.), Brisbane, Australia; Centre for Genomics Research (S.P.), Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK; Institute for Genomic Medicine (E.L.H.), Columbia University Medical Center, New York, NY; Murdoch Children's Research Institute (M.S.H., I.E.S.), Parkville; Department of Paediatrics (I.E.S.), Royal Children's Hospital, University of Melbourne; Florey Institute of Neuroscience and Mental Health (I.E.S.), Melbourne; and Healthy Mothers, Babies and Children (J.G.), South Australian Health and Medical Research Institute, Adelaide, Australia.

Objective: To identify the causative gene in a large unsolved family with genetic epilepsy with febrile seizures plus (GEFS+), we sequenced the genomes of family members, and then determined the contribution of the identified gene to the pathogenicity of epilepsies by examining sequencing data from 2,772 additional patients.

Methods: We performed whole genome sequencing of 3 members of a GEFS+ family. Subsequently, whole exome sequencing data from 1,165 patients with epilepsy from the Epi4K dataset and 1,329 Australian patients with epilepsy from the Epi25 dataset were interrogated. Targeted resequencing was performed on 278 patients with febrile seizures or GEFS+ phenotypes. Variants were validated and familial segregation examined by Sanger sequencing.

Results: Eight previously unreported missense variants were identified in , coding for the vesicular inhibitory amino acid cotransporter VGAT. Two variants cosegregated with the phenotype in 2 large GEFS+ families containing 8 and 10 affected individuals, respectively. Six further variants were identified in smaller families with GEFS+ or idiopathic generalized epilepsy (IGE).

Conclusion: Missense variants in cause GEFS+ and IGE. These variants are predicted to alter γ-aminobutyric acid (GABA) transport into synaptic vesicles, leading to altered neuronal inhibition. Examination of further epilepsy cohorts will determine the full genotype-phenotype spectrum associated with variants.
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http://dx.doi.org/10.1212/WNL.0000000000011855DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8166436PMC
May 2021

Seizures in Sotos syndrome: Phenotyping in 49 patients.

Epilepsia Open 2021 Jun 9;6(2):425-430. Epub 2021 Apr 9.

Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada.

We aimed to describe the phenotypic spectrum of seizures in Sotos syndrome, a genetic condition involving overgrowth, macrocephaly, dysmorphic features, and learning disability, in which 60%-90% have NSD1 pathogenic variants. Patients were recruited from clinics and referral from support groups. Those with seizures and a clinical diagnosis of Sotos syndrome were included. Phenotyping data were collected via structured clinical interview and chart review. Forty-nine patients were included. Twenty had NSD1 testing results available; of these, 15 (75%) had NSD1 pathogenic variants. Seizure onset age ranged from 3 months to 12 years. Staring spells (absence or focal impaired awareness seizure) were the most frequently reported semiology (33/49; 67%), followed by febrile seizures (25/49; 51%) and afebrile bilateral tonic-clonic seizures (25/49; 51%). Most patients (33/49; 67%) had multiple seizure types. The majority (33/49; 67%) had seizures controlled on a single antiseizure medication or no medication. Nine (18%) had drug-resistant epilepsy. Epilepsy syndromes included febrile seizures plus, Lennox-Gastaut syndrome, childhood absence epilepsy, and generalized tonic-clonic seizures alone. The seizure phenotype in Sotos syndrome most commonly involves staring spells, afebrile tonic-clonic seizures or febrile convulsions; however, other seizure types may occur. Seizures are typically well-controlled with medication, but drug-resistant epilepsy occurs in a minority.
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http://dx.doi.org/10.1002/epi4.12484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8166795PMC
June 2021

The Australian Academy of Health and Medical Sciences: an authoritative, independent voice in the Australian landscape.

Med J Aust 2021 Jun 24;214(11):502-504.e1. Epub 2021 May 24.

Translational Research Institute, University of Queensland, Brisbane, QLD.

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http://dx.doi.org/10.5694/mja2.51089DOI Listing
June 2021

Loss-of-function variants in K 11.1 cardiac channels as a biomarker for SUDEP.

Ann Clin Transl Neurol 2021 May 18. Epub 2021 May 18.

The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.

Objective: To compare the frequency and impact on the channel function of KCNH2 variants in SUDEP patients with epilepsy controls comprising patients older than 50 years, a group with low SUDEP risk, and establish loss-of-function KCNH2 variants as predictive biomarkers of SUDEP risk.

Methods: We searched for KCNH2 variants with a minor allele frequency of <5%. Functional analysis in Xenopus laevis oocytes was performed for all KCNH2 variants identified.

Results: KCNH2 variants were found in 11.1% (10/90) of SUDEP individuals compared to 6.0% (20/332) of epilepsy controls (p = 0.11). Loss-of-function KCNH2 variants, defined as causing >20% reduction in maximal amplitude, were observed in 8.9% (8/90) SUDEP patients compared to 3.3% (11/332) epilepsy controls suggesting about threefold enrichment (nominal p = 0.04). KCNH2 variants that did not change channel function occurred at a similar frequency in SUDEP (2.2%; 2/90) and epilepsy control (2.7%; 9/332) cohorts (p > 0.99). Rare KCNH2 variants (<1% allele frequency) associated with greater loss of function and an ~11-fold enrichment in the SUDEP cohort (nominal p = 0.03). In silico tools were unable to predict the impact of a variant on function highlighting the need for electrophysiological analysis.

Interpretation: These data show that loss-of-function KCNH2 variants are enriched in SUDEP patients when compared to an epilepsy population older than 50 years, suggesting that cardiac mechanisms contribute to SUDEP risk. We propose that genetic screening in combination with functional analysis can identify loss-of-function KCNH2 variants that could act as biomarkers of an individual's SUDEP risk.
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http://dx.doi.org/10.1002/acn3.51381DOI Listing
May 2021

Phenotypic Spectrum of Seizure Disorders in MBD5-Associated Neurodevelopmental Disorder.

Neurol Genet 2021 Apr 18;7(2):e579. Epub 2021 Mar 18.

Research Institute of the McGill University Health Centre (K.M.), Montreal, PQ; Division of Child Neurology (K.M.), Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, PQ; Department of Neurology & Neurosurgery (K.M.), Montreal Children's Hospital, McGill University, Montreal, PQ; Child Neurology and Psychiatry (C.M.), Salesi Pediatric Hospital, United Hospitals of Ancona, Ancona, Italy; Division of Genetic Medicine (G.L.C., J.N., H.C.M.), Department of Pediatrics, University of Washington, Seattle, WA; Department of Neurology (A.M.), Great Ormond Street Hospital for Children, London, UK; Developmental Neurosciences Programme (A.M.), UCL Great Ormond Street Institute of Child Health, London, UK; Neurology Network Melbourne (J.P.), Melbourne, Victoria, Australia; Murdoch Children's Research Institute (C.S., I.E.S.), Parkville, Victoria, Australia; Department of Paediatrics and Child Health (T.S.), School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand; Division of Neurology (S.M.), Department of Pediatrics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada; Neurology Unit and Neurogenetic Laboratories (C.B., A.R., R.G.), Meyer Children's Hospital, Florence, Italy; Department of Clinical Genetics (R.H.S.), Great Ormond Street Hospital, London, UK; Epilepsy Research Centre (I.E.S.), Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; Department of Paediatrics (I.E.S.), Royal Children's Hospital, The University of Melbourne, Parkville, Victoria, Australia; and The Florey Institute of Neuroscience and Mental Health (I.E.S.), Heidelberg, Victoria, Australia.

Objective: 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.

Methods: We performed phenotyping on patients with deletions, duplications, or point mutations and a history of seizures.

Results: 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.

Conclusions: 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.
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http://dx.doi.org/10.1212/NXG.0000000000000579DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8075573PMC
April 2021

Guidelines on the diagnosis, clinical assessments, treatment and management for CLN2 disease patients.

Orphanet J Rare Dis 2021 Apr 21;16(1):185. Epub 2021 Apr 21.

Evelina, London Children's Hospital, London, UK.

Background: CLN2 disease (Neuronal Ceroid Lipofuscinosis Type 2) is an ultra-rare, neurodegenerative lysosomal storage disease, caused by an enzyme deficiency of tripeptidyl peptidase 1 (TPP1). Lack of disease awareness and the non-specificity of presenting symptoms often leads to delayed diagnosis. These guidelines provide robust evidence-based, expert-agreed recommendations on the risks/benefits of disease-modifying treatments and the medical interventions used to manage this condition.

Methods: An expert mapping tool process was developed ranking multidisciplinary professionals, with knowledge of CLN2 disease, diagnostic or management experience of CLN2 disease, or family support professionals. Individuals were sequentially approached to identify two chairs, ensuring that the process was transparent and unbiased. A systematic literature review of published evidence using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance was independently and simultaneously conducted to develop key statements based upon the strength of the publications. Clinical care statements formed the basis of an international modified Delphi consensus determination process using the virtual meeting (Within3) online platform which requested experts to agree or disagree with any changes. Statements reaching the consensus mark became the guiding statements within this manuscript, which were subsequently assessed against the Appraisal of Guidelines for Research and Evaluation (AGREEII) criteria.

Results: Twenty-one international experts from 7 different specialities, including a patient advocate, were identified. Fifty-three guideline statements were developed covering 13 domains: General Description and Statements, Diagnostics, Clinical Recommendations and Management, Assessments, Interventions and Treatment, Additional Care Considerations, Social Care Considerations, Pain Management, Epilepsy / Seizures, Nutritional Care Interventions, Respiratory Health, Sleep and Rest, and End of Life Care. Consensus was reached after a single round of voting, with one exception which was revised, and agreed by 100% of the SC and achieved 80% consensus in the second voting round. The overall AGREE II assessment score obtained for the development of the guidelines was 5.7 (where 1 represents the lowest quality, and 7 represents the highest quality).

Conclusion: This program provides robust evidence- and consensus-driven guidelines that can be used by all healthcare professionals involved in the management of patients with CLN2 disease and other neurodegenerative disorders. This addresses the clinical need to complement other information available.
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http://dx.doi.org/10.1186/s13023-021-01813-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8059011PMC
April 2021

ATP1A2- and ATP1A3-associated early profound epileptic encephalopathy and polymicrogyria.

Brain 2021 Apr 21. Epub 2021 Apr 21.

Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children's Hospital, University of Florence, Florence, Italy.

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 individuals 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 individual). 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 individuals 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.
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http://dx.doi.org/10.1093/brain/awab052DOI Listing
April 2021

Cation leak underlies neuronal excitability in an HCN1 developmental and epileptic encephalopathy.

Brain 2021 Apr 1. Epub 2021 Apr 1.

Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.

Pathogenic variants in HCN1 are associated with developmental and epileptic encephalopathies. The recurrent de novo HCN1 M305L pathogenic variant is associated with severe developmental impairment and drug-resistant epilepsy. We engineered the homologue Hcn1 M294L heterozygous knock-in (Hcn1M294L) mouse to explore the disease mechanism underlying an HCN1 developmental and epileptic encephalopathy. The Hcn1M294L mouse recapitulated the phenotypic features of patients with the HCN1 M305L variant, including spontaneous seizures and a learning deficit. Active epileptiform spiking on the electrocorticogram and morphological markers typical of rodent seizure models were observed in the Hcn1M294L mouse. Lamotrigine exacerbated seizures and increased spiking, whereas sodium valproate reduced spiking, mirroring drug responses reported in a patient with this variant. Functional analysis in Xenopus laevis oocytes and layer V somatosensory cortical pyramidal neurons in ex vivo tissue revealed a loss of voltage dependence for the disease variant resulting in a constitutively open channel that allowed for cation 'leak' at depolarised membrane potentials. Consequently, Hcn1M294L layer V somatosensory cortical pyramidal neurons were significantly depolarised at rest. These neurons adapted through a depolarising shift in action potential threshold. Despite this compensation, layer V somatosensory cortical pyramidal neurons fired action potentials more readily from rest. A similar depolarised resting potential and left-shift in rheobase was observed for CA1 hippocampal pyramidal neurons. The Hcn1M294L mouse provides insight into the pathological mechanisms underlying hyperexcitability in HCN1 developmental and epileptic encephalopathy, as well as being a preclinical model with strong construct and face validity, on which potential treatments can be tested.
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http://dx.doi.org/10.1093/brain/awab145DOI Listing
April 2021

Progressive myoclonus epilepsies-Residual unsolved cases have marked genetic heterogeneity including dolichol-dependent protein glycosylation pathway genes.

Am J Hum Genet 2021 04;108(4):722-738

Neurology - Neurophysiology Unit, ASST dei Sette Laghi, Galmarini Tradate Hospital, Tradate 21049, Italy.

Progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous rare diseases. Over 70% of PME cases can now be molecularly solved. Known PME genes encode a variety of proteins, many involved in lysosomal and endosomal function. We performed whole-exome sequencing (WES) in 84 (78 unrelated) unsolved PME-affected individuals, with or without additional family members, to discover novel causes. We identified likely disease-causing variants in 24 out of 78 (31%) unrelated individuals, despite previous genetic analyses. The diagnostic yield was significantly higher for individuals studied as trios or families (14/28) versus singletons (10/50) (OR = 3.9, p value = 0.01, Fisher's exact test). The 24 likely solved cases of PME involved 18 genes. First, we found and functionally validated five heterozygous variants in NUS1 and DHDDS and a homozygous variant in ALG10, with no previous disease associations. All three genes are involved in dolichol-dependent protein glycosylation, a pathway not previously implicated in PME. Second, we independently validate SEMA6B as a dominant PME gene in two unrelated individuals. Third, in five families, we identified variants in established PME genes; three with intronic or copy-number changes (CLN6, GBA, NEU1) and two very rare causes (ASAH1, CERS1). Fourth, we found a group of genes usually associated with developmental and epileptic encephalopathies, but here, remarkably, presenting as PME, with or without prior developmental delay. Our systematic analysis of these cases suggests that the small residuum of unsolved cases will most likely be a collection of very rare, genetically heterogeneous etiologies.
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http://dx.doi.org/10.1016/j.ajhg.2021.03.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8059372PMC
April 2021

Cerebrospinal fluid liquid biopsy for detecting somatic mosaicism in brain.

Brain Commun 2021 21;3(1):fcaa235. Epub 2021 Jan 21.

Department of Medicine (Austin Health), University of Melbourne, Melbourne, Victoria 3084, Australia.

Brain somatic mutations are an increasingly recognized cause of epilepsy, brain malformations and autism spectrum disorders and may be a hidden cause of other neurodevelopmental and neurodegenerative disorders. At present, brain mosaicism can be detected only in the rare situations of autopsy or brain biopsy. Liquid biopsy using cell-free DNA derived from cerebrospinal fluid has detected somatic mutations in malignant brain tumours. Here, we asked if cerebrospinal fluid liquid biopsy can be used to detect somatic mosaicism in non-malignant brain diseases. First, we reliably quantified cerebrospinal fluid cell-free DNA in 28 patients with focal epilepsy and 28 controls using droplet digital PCR. Then, in three patients we identified somatic mutations in cerebrospinal fluid: in one patient with subcortical band heterotopia the p. Lys64* variant at 9.4% frequency; in a second patient with focal cortical dysplasia the p. Phe581His*6 variant at 7.8% frequency; and in a third patient with ganglioglioma the p. Val600Glu variant at 3.2% frequency. To determine if cerebrospinal fluid cell-free DNA was brain-derived, whole-genome bisulphite sequencing was performed and brain-specific DNA methylation patterns were found to be significantly enriched ( = 0.03). Our proof of principle study shows that cerebrospinal fluid liquid biopsy is valuable in investigating mosaic neurological disorders where brain tissue is unavailable.
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http://dx.doi.org/10.1093/braincomms/fcaa235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7954394PMC
January 2021

The aetiologies of epilepsy.

Epileptic Disord 2021 Feb;23(1):1-16

UCL Queen Square Institute of Neurology, Member of the ERN EpiCARE, London, UK.

The identification of the aetiology of a patient's epilepsy is instrumental in the diagnosis, prognostic counselling and management of the epilepsies. Indeed, the aetiology can be important for determining the recurrence risk of single seizures and so for making a diagnosis of epilepsy. Here, we divide the aetiologies into six categories: structural, genetic, infectious, metabolic, immune (all of which are part of the International League Against Epilepsy [ILAE] classification system) and neurodegenerative (which we have considered separately because of its growing importance in epilepsy). These are not mutually exclusive categories and many aetiologies fall into more than one category. Indeed, genetic factors probably play a role, to varying degrees, in the risk of seizures in all people with epilepsy. In each of the categories, we discuss what we regard as the most important aetiologies; importance being determined not only by prevalence but also by clinical significance. The introduction contains information suitable for level 1 competency (entry level), whilst the subsequent sections contain information aimed at level 2 competency (proficiency level) as part of the new ILAE competency-based curriculum. As we move towards precision medicine and targeted therapies, so aetiologies will play an even greater role in the management of epilepsy.
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http://dx.doi.org/10.1684/epd.2021.1255DOI Listing
February 2021

Speech, Language, and Oromotor Skills in Patients With Polymicrogyria.

Neurology 2021 04 15;96(14):e1898-e1912. Epub 2021 Feb 15.

From Murdoch Children's Research Institute (R.O.B., J.O.B., C.A.S., K.P., R.J.L., I.E.S., A.T.M.); Departments of Audiology and Speech Pathology (R.O.B., J.O.B., A.T.M.) and Paediatrics (C.A.S., R.J.L., I.E.S.), University of Melbourne; The Royal Children's Hospital (C.A.S., K.P., R.J.L., I.E.S., A.T.M.); Victorian Clinical Genetics Service (C.A.S., K.P.), Parkville, Victoria; Hunter Genetics (H.G.), John Hunter Hospital, New Lambton Heights, New South Wales; Austin Health (I.E.S.), Heidelberg, Victoria; and Florey Institute of Neuroscience and Mental Health (I.E.S.), Parkville, Victoria, Australia.

Objective: To determine whether specific speech, language, and oromotor profiles are associated with different patterns of polymicrogyria, we assessed 52 patients with polymicrogyria using a battery of standardized tests and correlated findings with topography and severity of polymicrogyria.

Methods: Patients were identified via clinical research databases and invited to participate, irrespective of cognitive and verbal language abilities. We conducted standardized assessments of speech, oromotor structure and function, language, and nonverbal IQ. Data were analyzed according to normative assessment data and descriptive statistics. We conducted a correlation analysis between topographic pattern and speech and language findings.

Results: Fifty-two patients (33 male, 63%) were studied at an average age of 12.7 years (range 2.5-36 years). All patients had dysarthria, which ranged from mild impairment to anarthria. Developmental speech errors (articulation and phonology), oral motor structure and function deficits, and language disorder were frequent. A total of 23/29 (79%) had cognitive abilities in the low average to extremely low range. In the perisylvian polymicrogyria group (36/52), speech, everyday language, and oral motor impairments were more severe, compared to generalized (1 patient), frontal (3), polymicrogyria with periventricular nodular heterotopia (3), parasagittal parieto-occipital (1), mesial occipital (1), and other (7) patterns.

Conclusions: Dysarthria is a core feature of polymicrogyria, often accompanied by receptive and expressive language impairments. These features are associated with all polymicrogyria distribution patterns and more severe in individuals with bilateral polymicrogyria, particularly in the perisylvian region.
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http://dx.doi.org/10.1212/WNL.0000000000011698DOI Listing
April 2021

Climate change and epilepsy: Insights from clinical and basic science studies.

Epilepsy Behav 2021 03 10;116:107791. Epub 2021 Feb 10.

Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK and Chalfont Centre for Epilepsy, Bucks, UK. Electronic address:

Climate change is with us. As professionals who place value on evidence-based practice, climate change is something we cannot ignore. The current pandemic of the novel coronavirus, SARS-CoV-2, has demonstrated how global crises can arise suddenly and have a significant impact on public health. Global warming, a chronic process punctuated by acute episodes of extreme weather events, is an insidious global health crisis needing at least as much attention. Many neurological diseases are complex chronic conditions influenced at many levels by changes in the environment. This review aimed to collate and evaluate reports from clinical and basic science about the relationship between climate change and epilepsy. The keywords climate change, seasonal variation, temperature, humidity, thermoregulation, biorhythm, gene, circadian rhythm, heat, and weather were used to search the published evidence. A number of climatic variables are associated with increased seizure frequency in people with epilepsy. Climate change-induced increase in seizure precipitants such as fevers, stress, and sleep deprivation (e.g. as a result of more frequent extreme weather events) or vector-borne infections may trigger or exacerbate seizures, lead to deterioration of seizure control, and affect neurological, cerebrovascular, or cardiovascular comorbidities and risk of sudden unexpected death in epilepsy. Risks are likely to be modified by many factors, ranging from individual genetic variation and temperature-dependent channel function, to housing quality and global supply chains. According to the results of the limited number of experimental studies with animal models of seizures or epilepsy, different seizure types appear to have distinct susceptibility to seasonal influences. Increased body temperature, whether in the context of fever or not, has a critical role in seizure threshold and seizure-related brain damage. Links between climate change and epilepsy are likely to be multifactorial, complex, and often indirect, which makes predictions difficult. We need more data on possible climate-driven altered risks for seizures, epilepsy, and epileptogenesis, to identify underlying mechanisms at systems, cellular, and molecular levels for better understanding of the impact of climate change on epilepsy. Further focussed data would help us to develop evidence for mitigation methods to do more to protect people with epilepsy from the effects of climate change.
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http://dx.doi.org/10.1016/j.yebeh.2021.107791DOI Listing
March 2021

The severe epilepsy syndromes of infancy: A population-based study.

Epilepsia 2021 02 21;62(2):358-370. Epub 2021 Jan 21.

Department of Neurology, Royal Children's Hospital, Melbourne, Vic, Australia.

Objective: To study the epilepsy syndromes among the severe epilepsies of infancy and assess their incidence, etiologies, and outcomes.

Methods: A population-based cohort study was undertaken of severe epilepsies with onset before age 18 months in Victoria, Australia. Two epileptologists reviewed clinical features, seizure videos, and electroencephalograms to diagnose International League Against Epilepsy epilepsy syndromes. Incidence, etiologies, and outcomes at age 2 years were determined.

Results: Seventy-three of 114 (64%) infants fulfilled diagnostic criteria for epilepsy syndromes at presentation, and 16 (14%) had "variants" of epilepsy syndromes in which there was one missing or different feature, or where all classical features had not yet emerged. West syndrome (WS) and "WS-like" epilepsy (infantile spasms without hypsarrhythmia or modified hypsarrhythmia) were the most common syndromes, with a combined incidence of 32.7/100 000 live births/year. The incidence of epilepsy of infancy with migrating focal seizures (EIMFS) was 4.5/100 000 and of early infantile epileptic encephalopathy (EIEE) was 3.6/100 000. Structural etiologies were common in "WS-like" epilepsy (100%), unifocal epilepsy (83%), and WS (39%), whereas single gene disorders predominated in EIMFS, EIEE, and Dravet syndrome. Eighteen (16%) infants died before age 2 years. Development was delayed or borderline in 85 of 96 (89%) survivors, being severe-profound in 40 of 96 (42%). All infants with EIEE or EIMFS had severe-profound delay or were deceased, but only 19 of 64 (30%) infants with WS, "WS-like," or "unifocal epilepsy" had severe-profound delay, and only two of 64 (3%) were deceased.

Significance: Three quarters of severe epilepsies of infancy could be assigned an epilepsy syndrome or "variant syndrome" at presentation. In this era of genomic testing and advanced brain imaging, diagnosing epilepsy syndromes at presentation remains clinically useful for guiding etiologic investigation, initial treatment, and prognostication.
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http://dx.doi.org/10.1111/epi.16810DOI Listing
February 2021

Contribution of rare genetic variants to drug response in absence epilepsy.

Epilepsy Res 2021 Feb 4;170:106537. Epub 2021 Jan 4.

Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, 245 Burgundy St, Heidelberg, VIC, 3084, Australia; Department of Neurology, Royal Children's Hospital, The University of Melbourne, 50 Flemington Rd, Parkville, VIC, 3052, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia; Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia.

Objective: We investigated the possible significance of rare genetic variants to response to valproic acid (VPA) and ethosuximide (ETX) in patients with absence epilepsy. Our primary hypothesis was that rare CACNA1H variants are more frequent in ETX-non-responsive patients compared to ETX-responsive. Our secondary hypothesis was that rare variants in GABA-receptor genes are more frequent in VPA-non-responsive patients compared to VPA-responsive.

Methods: We recruited patients with absence epilepsy treated with both VPA and ETX, and performed whole exome sequencing in order to investigate the potential role of rare variants in CACNA1H, other voltage-gated calcium channel (VGCC) genes, or GABA-receptor genes in predicting response to ETX or VPA.

Results: Sixty-two patients were included; 12 were ETX-responsive, 14 VPA-responsive, and 36 did not have a clear positive response to either medication. We did not find significant enrichment inCACNA1H rare variants in ETX-responsive patients (odds ratio 3.43; 0.43-27.65; p = 0.20), nor was there enrichment for other VGCC genes. No significant enrichment of GABA-receptor gene rare variants was seen for VPA-non-responsive patients versus VPA-responsive. We found enrichment of rare GABA-receptor variants in our absence cohort compared to controls (odds ratio 3.82; 1.68-8.69). There was no difference in frequency of CACNA1H rs61734410 and CACNA1I rs3747178 polymorphisms between ETX-responsive and ETX-non-responsive groups; these polymorphisms have previously been reported to predict lack of response to ETX in absence epilepsy.

Significance: We conclude that if CACNA1H rare variants predict lack of response to ETX, a larger sample is necessary to test this with sufficient power. Increased GABA-receptor gene rare variant frequency in absence epilepsy patients who fail initial anti-seizure therapy suggests subtle GABA receptor dysfunction may contribute to the underlying pathophysiology.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106537DOI Listing
February 2021

The phenotypic spectrum of X-linked, infantile onset ALG13-related developmental and epileptic encephalopathy.

Epilepsia 2021 02 7;62(2):325-334. Epub 2021 Jan 7.

Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.

Objective: Asparagine-linked glycosylation 13 (ALG13) deficiencies have been repeatedly described in the literature with the clinical phenotype of a developmental and epileptic encephalopathy (DEE). Most cases were females carrying the recurrent ALG13 de novo variant, p.(Asn107Ser), with normal transferrin electrophoresis.

Methods: We delineate the phenotypic spectrum of 38 individuals, 37 girls and one boy, 16 of them novel and 22 published, with the most common pathogenic ALG13 variant p.(Asn107Ser) and additionally report the phenotype of three individuals carrying other likely pathogenic ALG13 variants.

Results: The phenotypic spectrum often comprised pharmacoresistant epilepsy with epileptic spasms, mostly with onset within the first 6 months of life and with spasm persistence in one-half of the cases. Tonic seizures were the most prevalent additional seizure type. Electroencephalography showed hypsarrhythmia and at a later stage of the disease in one-third of all cases paroxysms of fast activity with electrodecrement. ALG13-related DEE was usually associated with severe to profound developmental delay; ambulation was acquired by one-third of the cases, whereas purposeful hand use was sparse or completely absent. Hand stereotypies and dyskinetic movements including dystonia or choreoathetosis were relatively frequent. Verbal communication skills were absent or poor, and eye contact and pursuit were often impaired.

Significance: X-linked ALG13-related DEE usually manifests as West syndrome with severe to profound developmental delay. It is predominantly caused by the recurrent de novo missense variant p.(Asn107Ser). Comprehensive functional studies will be able to prove or disprove an association with congenital disorder of glycosylation.
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http://dx.doi.org/10.1111/epi.16761DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7898319PMC
February 2021

Self-limited focal epilepsy and childhood apraxia of speech with WAC pathogenic variants.

Eur J Paediatr Neurol 2021 Jan 24;30:25-28. Epub 2020 Dec 24.

Division of Child Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada; Department of Neurology & Neurosurgery, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada. Electronic address:

Heterozygous pathogenic WAC variants cause Desanto-Shinawi syndrome; affected patients have dysmorphic features, developmental impairment and behavioral abnormalities. Seizures are reported in one quarter, including tonic-clonic, absence, and febrile seizures. This study aimed to better understand the phenotypic spectrum of epilepsy and development in Desanto-Shinawi syndrome. We identified four children with seizures and pathogenic WAC variants, including two siblings. All had global developmental impairment with language affected most severely; two had diagnoses of childhood apraxia of speech and two had autism spectrum disorder. Seizure onset age ranged from six months to 14 years. Seizures always occurred from sleep and were focal impaired awareness with motor features in three patients, with one having bilateral tonic-clonic seizures of suspected focal onset. Two patients had spontaneous seizure resolution without treatment, and the remaining two were well-controlled on monotherapy. EEG was normal in two patients; one had focal right frontal spikes in drowsiness and sleep while the last had independent centrotemporal spikes from both hemispheres, activated in sleep. All patients had heterozygous truncating pathogenic WAC variants, with negative parental testing. The findings in this cohort of patients suggest that epilepsy in Desanto-Shinawi syndrome is usually focal and self-limited, and may fall within the epilepsy-aphasia spectrum.
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http://dx.doi.org/10.1016/j.ejpn.2020.12.010DOI Listing
January 2021

FBXO28 causes developmental and epileptic encephalopathy with profound intellectual disability.

Epilepsia 2021 01 6;62(1):e13-e21. Epub 2020 Dec 6.

Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia.

Chromosome 1q41-q42 deletion syndrome is a rare cause of intellectual disability, seizures, dysmorphology, and multiple anomalies. Two genes in the 1q41-q42 microdeletion, WDR26 and FBXO28, have been implicated in monogenic disease. Patients with WDR26 encephalopathy overlap clinically with those with 1q41-q42 deletion syndrome, whereas only one patient with FBXO28 encephalopathy has been described. Seizures are a prominent feature of 1q41-q42 deletion syndrome; therefore, we hypothesized that pathogenic FBXO28 variants cause developmental and epileptic encephalopathies (DEEs). We describe nine new patients with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and analyze all 10 known cases to delineate the phenotypic spectrum. All patients had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features, albeit different to those typically seen in 1q41-q42 deletion syndrome and WDR26 encephalopathy. We distinguish FBXO28 encephalopathy from both of these disorders with more severe intellectual impairment, drug-resistant epilepsy, and hyperkinetic movement disorders.
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http://dx.doi.org/10.1111/epi.16784DOI Listing
January 2021

Transcriptome analysis of a ring chromosome 20 patient cohort.

Epilepsia 2021 01 18;62(1):e22-e28. Epub 2020 Nov 18.

Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia.

Ring chromosomes occur when the ends of normally rod-shaped chromosomes fuse. In ring chromosome 20 (ring 20), intellectual disability and epilepsy are usually present, even if there is no deleted coding material; the mechanism by which individuals with complete ring chromosomes develop seizures and other phenotypic abnormalities is not understood. We investigated altered gene transcription as a contributing factor by performing RNA-sequencing (RNA-seq) analysis on blood from seven patients with ring 20, and 11 first-degree relatives (all parents). Geographic analysis did not identify altered expression in peritelomeric or other specific chromosome 20 regions. RNA-seq analysis revealed 97 genes potentially differentially expressed in ring 20 patients. These included one epilepsy gene, NPRL3, but this finding was not confirmed on reverse transcription Droplet Digital polymerase chain reaction analysis. Molecular studies of structural chromosomal anomalies such as ring chromosome are challenging and often difficult to interpret because many patients are mosaic, and there may be genome-wide chromosomal instability affecting gene expression. Our findings nevertheless suggest that peritelomeric altered transcription is not the likely pathogenic mechanism in ring 20. Underlying genetic mechanisms are likely complex and may involve differential expression of many genes, the majority of which may not be located on chromosome 20.
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http://dx.doi.org/10.1111/epi.16766DOI Listing
January 2021

NEXMIF encephalopathy: an X-linked disorder with male and female phenotypic patterns.

Genet Med 2021 02 4;23(2):363-373. Epub 2020 Nov 4.

Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA.

Purpose: Pathogenic variants in the X-linked gene NEXMIF (previously KIAA2022) are associated with intellectual disability (ID), autism spectrum disorder, and epilepsy. We aimed to delineate the female and male phenotypic spectrum of NEXMIF encephalopathy.

Methods: Through an international collaboration, we analyzed the phenotypes and genotypes of 87 patients with NEXMIF encephalopathy.

Results: Sixty-three females and 24 males (46 new patients) with NEXMIF encephalopathy were studied, with 30 novel variants. Phenotypic features included developmental delay/ID in 86/87 (99%), seizures in 71/86 (83%) and multiple comorbidities. Generalized seizures predominated including myoclonic seizures and absence seizures (both 46/70, 66%), absence with eyelid myoclonia (17/70, 24%), and atonic seizures (30/70, 43%). Males had more severe developmental impairment; females had epilepsy more frequently, and varied from unaffected to severely affected. All NEXMIF pathogenic variants led to a premature stop codon or were deleterious structural variants. Most arose de novo, although X-linked segregation occurred for both sexes. Somatic mosaicism occurred in two males and a family with suspected parental mosaicism.

Conclusion: NEXMIF encephalopathy is an X-linked, generalized developmental and epileptic encephalopathy characterized by myoclonic-atonic epilepsy overlapping with eyelid myoclonia with absence. Some patients have developmental encephalopathy without epilepsy. Males have more severe developmental impairment. NEXMIF encephalopathy arises due to loss-of-function variants.
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http://dx.doi.org/10.1038/s41436-020-00988-9DOI Listing
February 2021

Tracing Autism Traits in Large Multiplex Families to Identify Endophenotypes of the Broader Autism Phenotype.

Int J Mol Sci 2020 Oct 27;21(21). Epub 2020 Oct 27.

Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, VIC 3084, Australia.

Families comprising many individuals with Autism Spectrum Disorders (ASD) may carry a dominant predisposing mutation. We implemented rigorous phenotyping of the "Broader Autism Phenotype" (BAP) in large multiplex ASD families using a novel endophenotype approach for the identification and characterisation of distinct BAP endophenotypes. We evaluated ASD/BAP features using standardised tests and a semi-structured interview to assess social, intellectual, executive and adaptive functioning in 110 individuals, including two large multiplex families (Family A: 30; Family B: 35) and an independent sample of small families ( = 45). Our protocol identified four distinct psychological endophenotypes of the BAP that were evident across these independent samples, and showed high sensitivity (97%) and specificity (82%) for individuals classified with the BAP. Patterns of inheritance of identified endophenotypes varied between the two large multiplex families, supporting their utility for identifying genes in ASD.
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http://dx.doi.org/10.3390/ijms21217965DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663259PMC
October 2020

Fenfluramine HCl (Fintepla ) provides long-term clinically meaningful reduction in seizure frequency: Analysis of an ongoing open-label extension study.

Epilepsia 2020 11 19;61(11):2396-2404. Epub 2020 Oct 19.

Zogenix, Inc, Emeryville, CA, USA.

Objective: Fenfluramine has been shown to provide clinically meaningful and statistically significant reductions in convulsive seizure frequency in children and adolescents (aged 2-18 years) with Dravet syndrome in two randomized, placebo-controlled clinical trials. The objective of this analysis was to assess longer-term safety and efficacy of fenfluramine in patients who completed one of the double-blind studies and entered an open-label extension (OLE) study.

Methods: Patients enrolling in the OLE study initiated fenfluramine at 0.2 mg/kg/d regardless of their treatment assignment in the double-blind study. After 4 weeks, the fenfluramine dose could be titrated based on efficacy and tolerability to maximum of 0.7 mg/kg/d (absolute maximum 27 mg/d) or maximum of 0.4 mg/kg/d (absolute maximum 17 mg/d) in patients receiving concomitant stiripentol. The number and type of seizures were recorded daily in an electronic diary, and safety, including echocardiography, was assessed at Months 1, 2, and 3, and at 3-month intervals thereafter.

Results: A total of 232 patients were enrolled as of March 13, 2018. During this analysis period, patients were treated for a median 256 days (range = 46-634 days). Over the entire OLE analysis period, the median decrease in convulsive seizure frequency compared to baseline in the double-blind studies was -66.8% (range = -100% to 234.9%; P < .001). The median reduction in seizure frequency was similar in patients <6 (-75.7%) and ≥6 years old (-64.7%). The most commonly reported adverse events included pyrexia (21.6%), nasopharyngitis (19.4%), and decreased appetite (-15.9%). No valvular heart disease (VHD) or pulmonary arterial hypertension (PAH) was observed.

Significance: Study results demonstrate that fenfluramine provides clinically meaningful (≥50%) seizure frequency reduction over an extended period in patients with Dravet syndrome. No patient developed VHD or PAH, and fenfluramine was generally well tolerated.
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http://dx.doi.org/10.1111/epi.16722DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756901PMC
November 2020

Germline and Mosaic Variants in PRKACA and PRKACB Cause a Multiple Congenital Malformation Syndrome.

Am J Hum Genet 2020 11 14;107(5):977-988. Epub 2020 Oct 14.

Department of Clinical Genetics, Division of Human Genetics and Genome Research, Center of Excellence for Human Genetics, National Research Centre, Cairo, 12622, Egypt.

PRKACA and PRKACB code for two catalytic subunits (Cα and Cβ) of cAMP-dependent protein kinase (PKA), a pleiotropic holoenzyme that regulates numerous fundamental biological processes such as metabolism, development, memory, and immune response. We report seven unrelated individuals presenting with a multiple congenital malformation syndrome in whom we identified heterozygous germline or mosaic missense variants in PRKACA or PRKACB. Three affected individuals were found with the same PRKACA variant, and the other four had different PRKACB mutations. In most cases, the mutations arose de novo, and two individuals had offspring with the same condition. Nearly all affected individuals and their affected offspring shared an atrioventricular septal defect or a common atrium along with postaxial polydactyly. Additional features included skeletal abnormalities and ectodermal defects of variable severity in five individuals, cognitive deficit in two individuals, and various unusual tumors in one individual. We investigated the structural and functional consequences of the variants identified in PRKACA and PRKACB through the use of several computational and experimental approaches, and we found that they lead to PKA holoenzymes which are more sensitive to activation by cAMP than are the wild-type proteins. Furthermore, expression of PRKACA or PRKACB variants detected in the affected individuals inhibited hedgehog signaling in NIH 3T3 fibroblasts, thereby providing an underlying mechanism for the developmental defects observed in these cases. Our findings highlight the importance of both Cα and Cβ subunits of PKA during human development.
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http://dx.doi.org/10.1016/j.ajhg.2020.09.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7675002PMC
November 2020

Are Variants Causing Cardiac Arrhythmia Risk Factors in Sudden Unexpected Death in Epilepsy?

Front Neurol 2020 8;11:925. Epub 2020 Sep 8.

Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.

Sudden unexpected death in epilepsy (SUDEP) is the most common cause of premature mortality in individuals with epilepsy. Acute and adaptive changes in heart rhythm in epilepsy implicate cardiac dysfunction as a potential pathogenic mechanism in SUDEP. Furthermore, variants in genes associated with Long QT syndrome (LQTS) have been identified in patients with SUDEP. LQTS is a cardiac arrhythmia condition that causes sudden cardiac death with strong similarities to SUDEP. Here, we discuss the possibility of an additive risk of death due to the functional consequences of a pathogenic variant in an LQTS gene interacting with seizure-mediated changes in cardiac function. Extending this general concept, we propose a hypothesis that common variants in LQTS genes, which cause a subtle impact on channel function and would not normally be considered risk factors for cardiac disease, may increase the risk of sudden death when combined with epilepsy. A greater understanding of the interaction between epilepsy, cardiac arrhythmia, and SUDEP will inform our understanding of SUDEP risk and subsequent potential prophylactic treatment.
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http://dx.doi.org/10.3389/fneur.2020.00925DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7505992PMC
September 2020

Large-scale targeted sequencing identifies risk genes for neurodevelopmental disorders.

Nat Commun 2020 10 1;11(1):4932. Epub 2020 Oct 1.

Oasi Research Institute-IRCCS, Troina, Italy.

Most genes associated with neurodevelopmental disorders (NDDs) were identified with an excess of de novo mutations (DNMs) but the significance in case-control mutation burden analysis is unestablished. Here, we sequence 63 genes in 16,294 NDD cases and an additional 62 genes in 6,211 NDD cases. By combining these with published data, we assess a total of 125 genes in over 16,000 NDD cases and compare the mutation burden to nonpsychiatric controls from ExAC. We identify 48 genes (25 newly reported) showing significant burden of ultra-rare (MAF < 0.01%) gene-disruptive mutations (FDR 5%), six of which reach family-wise error rate (FWER) significance (p < 1.25E-06). Among these 125 targeted genes, we also reevaluate DNM excess in 17,426 NDD trios with 6,499 new autism trios. We identify 90 genes enriched for DNMs (FDR 5%; e.g., GABRG2 and UIMC1); of which, 61 reach FWER significance (p < 3.64E-07; e.g., CASZ1). In addition to doubling the number of patients for many NDD risk genes, we present phenotype-genotype correlations for seven risk genes (CTCF, HNRNPU, KCNQ3, ZBTB18, TCF12, SPEN, and LEO1) based on this large-scale targeted sequencing effort.
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http://dx.doi.org/10.1038/s41467-020-18723-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530681PMC
October 2020

Genetic Contributions to Acquired Epilepsies.

Epilepsy Curr 2021 Jan-Feb;21(1):5-13. Epub 2020 Sep 29.

Department of Medicine, 2281Epilepsy Research Centre, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia.

Whether genetic factors contribute to acquired epilepsies has long been controversial. Supporters observe that, among individuals exposed to seemingly the same brain insult, only a minority develops unprovoked seizures. Yet, only in relatively recent years have studies started to build a case for genetic contributions. Here, we appraise this emerging evidence, by providing a critical review of studies published in the field.
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http://dx.doi.org/10.1177/1535759720954254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7863311PMC
September 2020

Protocol for a single patient therapy plan: A randomised, double-blind, placebo-controlled N-of-1 trial to assess the efficacy of cannabidiol in patients with intractable epilepsy.

J Paediatr Child Health 2020 Dec 23;56(12):1918-1923. Epub 2020 Sep 23.

Royal Children's Hospital, Melbourne, Victoria, Australia.

Aim: This paper describes the use of the single patient therapy plan (SPTP). The SPTP has been designed to assess the efficacy at an individual level of a commercially available cannabinoid product, cannabidiol, in reducing seizure frequency in paediatric patients with intractable epilepsy.

Methods: The SPTP is a randomised, double-blind, placebo-controlled N-of-1 trial designed to assess the efficacy of treatment in a neurology outpatient setting. The primary objective of the SPTP is to assess the efficacy of cannabidiol in reducing seizure frequency in each patient with intractable epilepsy, with change in seizure frequency being the primary outcome of interest. The analysis adopts a Bayesian approach, which provides results in the form of posterior probabilities that various levels of benefit (based on the primary outcome measure, seizure frequency) have been achieved under active treatment compared to placebo, accompanied by decision rules that provide thresholds for deciding whether treatment has been successful in the individual patient. The SPTP arrangement is most accurately considered part of clinical practice rather than research, since it is aimed at making clinical treatment decisions for individual patients and is not testing a hypothesis or collecting aggregate data. Therefore, Human Research Ethics Committee approval was considered not to be required, although it is recommended that hospital Clinical Ethics Committees provide ethical oversight.

Conclusion: These SPTP resources are made available so that they may inform clinical practice in the treatment of severe epilepsy or adapted for use in other conditions.
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http://dx.doi.org/10.1111/jpc.15078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820972PMC
December 2020