Publications by authors named "Vincent des Portes"

92 Publications

SCN1A-related epilepsy with recessive inheritance: Two further families.

Eur J Paediatr Neurol 2021 Jul 5;33:121-124. Epub 2021 Jun 5.

APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France; Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France. Electronic address:

Background: Variants in SCN1A gene, encoding the voltage-gated sodium channel Na1.1, are associated with distinct epilepsy syndromes ranging from the relatively benign genetic epilepsy with febrile seizures plus (GEFS+) to Dravet syndrome, a severe developmental and epileptic encephalopathy (DEE). Most SCN1A pathogenic variants are heterozygous changes inherited in a dominant or de novo inheritance and many cause a loss-of-function of one allele. To date, recessive inheritance has been suggested in only two families with affected children harboring homozygous SCN1A missense variants while their heterozygous parents were asymptomatic. The aim of this report is to describe two additional families in which affected individuals have biallelic SCN1A variants possibly explaining their phenotype.

Methods And Results: We report two novel homozygous SCN1A missense variants in two patients from related parents. Both patients had fever-sensitive epilepsy beginning in the first months of life, followed by afebrile seizures, without severe cognitive impairment. Parents were asymptomatic. Next generation sequencing excluded a pathogenic variant in other genes involved in DEE. Estimation of pathogenicity scores by in-silico tools suggests that the impact of these SCN1A variants is less damaging than that of dominant pathogenic variants.

Conclusion: This study provides additional evidence that homozygous variants in SCN1A can cause GEFS+. This recessive inheritance would imply that hypomorphic variants may not necessarily cause epilepsy at the heterozygous state but may decrease the seizure threshold when combined.
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http://dx.doi.org/10.1016/j.ejpn.2021.05.018DOI Listing
July 2021

KCNT1-related epilepsies and epileptic encephalopathies: phenotypic and mutational spectrum.

Brain 2021 Jun 11. Epub 2021 Jun 11.

Pediatric Neurology Department, Lyon University Hospital, 69500 Bron, France.

Variants in KCNT1, encoding a sodium-gated potassium channel (subfamily T member 1), have been associated with a spectrum of epilepsies and neurodevelopmental disorders. These range from familial autosomal dominant or sporadic sleep-related hypermotor epilepsy ((AD)SHE) to epilepsy of infancy with migrating focal seizures (EIMFS) and include developmental and epileptic encephalopathies (DEE). This study aims to provide a comprehensive overview of the phenotypic and genotypic spectrum of KCNT1 mutation-related epileptic disorders in 248 individuals, including 66 unpreviously published and 182 published cases, the largest cohort reported so far. Four phenotypic groups emerged from our analysis: i) EIMFS (152 individuals, 33 previously unpublished); ii) DEE other than EIMFS (non-EIMFS DEE) (37 individuals, 17 unpublished); iii) (AD)SHE (53 patients, 14 unpublished); iv) other phenotypes (6 individuals, 2 unpublished). In our cohort of 66 new cases, the most common phenotypic features were: a) in EIMFS, heterogeneity of seizure types, including epileptic spasms, epilepsy improvement over time, no epilepsy-related deaths; b) in non-EIMFS DEE, possible onset with West syndrome, occurrence of atypical absences, possible evolution to DEE with SHE features; one case of sudden unexplained death in epilepsy (SUDEP); c) in (AD)SHE, we observed a high prevalence of drug-resistance, although seizure frequency improved with age in some individuals, appearance of cognitive regression after seizure onset in all patients, no reported severe psychiatric disorders, although behavioural/psychiatric comorbidities were reported in about 50% of the patients, SUDEP in one individual; d) other phenotypes in individuals with mutation of KCNT1 included temporal lobe epilepsy, and epilepsy with tonic-clonic seizures and cognitive regression. Genotypic analysis of the whole cohort of 248 individuals showed only missense mutations and one inframe deletion in KCNT1. Although the KCNT1 mutations in affected individuals were seen to be distributed among the different domains of the KCNT1 protein, genotype-phenotype considerations showed many of the (AD)SHE-associated mutations to be clustered around the RCK2 domain in the C-terminus, distal to the NADP domain. Mutations associated with EIMFS/non-EIMFS DEE did not show a particular pattern of distribution in the KCNT1 protein. Recurrent KCNT1 mutations were seen to be associated with both severe and less severe phenotypes. Our study further defines and broadens the phenotypic and genotypic spectrums of KCNT1-related epileptic conditions and emphasizes the increasingly important role of this gene in the pathogenesis of early onset DEEs as well as in focal epilepsies, namely (AD)SHE.
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http://dx.doi.org/10.1093/brain/awab219DOI Listing
June 2021

CACNA1A-associated epilepsy: Electroclinical findings and treatment response on seizures in 18 patients.

Eur J Paediatr Neurol 2021 Jul 26;33:75-85. Epub 2021 May 26.

Department of Pediatric Neurology and Neurosurgery, CHU Angers, France; Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, France.

CACNA1A pathogenic mutations are involved in various neurological phenotypes including episodic ataxia (EA2), spinocerebellar ataxia (SCA6), and familial hemiplegic migraine (FHM1). Epilepsy is poorly documented. We studied 18 patients (10 males) carrying de novo or inherited CACNA1A mutations, with median age of 2,5 years at epilepsy onset. Eight mutations were novel. Two variants known leading to gain of function (GOF) were found in 5 patients. Five other patients had non-sense variants leading to loss of function (LOF). Seizures were most often revealed by either status epilepticus (SE) (n = 8), eventually triggered by fever (n = 5), or absences/behavioural arrests (n = 7). Non-epileptic paroxysmal events were frequent and consisted in recurrent hemiplegic accesses (n = 9), jitteriness in the neonatal period (n = 6), and ocular paroxysmal events (n = 9). Most of the patients had early permanent cerebellar dysfunction (n = 16) and early moderate to severe global developmental delay (GDD)/intellectual deficiency (ID) (n = 17). MRI was often abnormal, with cerebellar (n = 8) and/or cerebral (n = 6) atrophy. Stroke-like occurred in 2 cases. Some antiepileptic drugs including topiramate, levetiracetam, lamotrigine and valproate were effective on seizures. Acetazolamide and calcium channel blockers were often effective when used. More than half of the patients had refractory epilepsy. CACNA1A mutation should be evoked in front of 2 main electro-clinical phenotypes that are associated with permanent cerebellar dysfunction and moderate to severe GDD/ID. The first one, found in all 5 patients with GOF variants, is characterized by intractable seizures, early and recurrent SE and hemiplegic accesses. The second, less severe, found in 5 patients with LOF variants, is characterized by refractory early onset absence seizures.
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http://dx.doi.org/10.1016/j.ejpn.2021.05.010DOI Listing
July 2021

Prenatal Imaging Features and Postnatal Outcome of Short Corpus Callosum: A Series of 42 Cases.

Fetal Diagn Ther 2021 8;48(3):217-226. Epub 2021 Mar 8.

Centre Pluridisciplinaire de Diagnostic Prénatal, Hôpital Femme Mère Enfant, Université Claude Bernard Lyon 1, Lyon-Bron, France,

Objectives: Our goal was to provide a better understanding of isolated short corpus callosum (SCC) regarding prenatal diagnosis and postnatal outcome.

Methods: We retrospectively reviewed prenatal and postnatal imaging, clinical, and biological data from 42 cases with isolated SCC.

Results: Prenatal imaging showed SCC in all cases (n = 42). SCC was limited to rostrum and/or genu and/or splenium in 21 cases, involved body in 16 cases, and was more extensive in 5 cases. Indirect imaging features included typical buffalo horn ventricles (n = 14), septal dysmorphism (n = 14), parallel lateral ventricles (n = 12), and ventriculomegaly (n = 4), as well as atypical features in 5 cases. SCC was associated with interhemispheric cysts and pericallosal lipomas in 3 and 6 cases, respectively. Aneuploidy was found in 2 cases. Normal psychomotor development, mild developmental disorders, and global developmental delay were found in 70, 15, and 15% of our cases, respectively.

Conclusions: SCC should be investigated to look for pericallosal lipoma and typical versus atypical indirect features of corpus callosum agenesis (CCA). Prenatal counselling should be guided by imaging as well as clinical and genetic context. Outcome of patients with SCC was similar to the one presenting with complete CCA.
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http://dx.doi.org/10.1159/000512953DOI Listing
March 2021

Normal intellectual skills in patients with Rhombencephalosynapsis.

Eur J Paediatr Neurol 2020 Nov 30;29:92-100. Epub 2020 Sep 30.

Department of Pediatric Neurology, Competence Centre for Cerebellar Malformations, Lyon University Hospital, F-69677, Bron, France; University Lyon 1, F-69008, Lyon, France. Electronic address:

Objectives: Rhombencephalosynapsis (RES) is a very rare cerebellar malformation. Neurodevelopmental outcome of apparently isolated RES remains poorly documented and standardized cognitive assessment, reported in only nine published cases so far, is lacking. Prenatal counselling is challenging considering the uncertain prognosis of isolated RES. The aim of this study was to focus on cognitive and motor outcome of isolated RES with a clinical description of six new cases and a detailed review of the literature.

Methods: A single-centre retrospective study of all RES patients over a 15-year period. Ataxia and fine motor skills were scored using a five-grade scale, according to the degree of disturbance of daily living. Intelligence Quotient (IQ) was established according to age-related Weschler Intelligence Scales. A systematic literature review included published cases with relevant outcome data.

Results: Six new cases of apparently isolated RES were reported, including three diagnosed in prenatal settings. The onset age for walking was delayed in four patients. Three patients had head shaking and three had a strabismus. One patient had a mild motor disability, one had subtle ataxia that did not impair daily life and four patients had a normal neurological examination at the last visit. Intellectual abilities were normal in all patients (full IQ score from 90 to 142), although three had ADHD. All received standard schooling. Based on these six new cases, as well as cases from 12 publications in the literature, a total of 28 patients with non-syndromic RES were analysed. Concerning motor outcome, 72% had no complaint or minimal impairment, 16% moderate and 12% severe impairment. Concerning cognitive outcome, 68% had normal cognitive skills, 18% borderline intellectual functioning and 14% moderate to severe disability.
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http://dx.doi.org/10.1016/j.ejpn.2020.09.007DOI Listing
November 2020

Intellectual disability.

Handb Clin Neurol 2020 ;174:113-126

Paediatric Neurology Department, Hôpital Femme Mère Enfants, University of Lyon, Bron, France; Rare Intellectual Disabilities Reference Centre, Institut des Sciences Cognitives, University of Lyon, Bron, France. Electronic address:

Intellectual disability (ID) or intellectual developmental disability (IDD) is one of the commonest neurodevelopmental disabilities worldwide and is known to affect 2% of the population of France or just over a million people. It is marked by a reduced ability to reason and understand abstract or complex information, which heavily restricts school learning and limits the individual's ability to adapt to daily life, including their transition to adulthood. Intellectual handicap or mental handicap results from an interaction between the individual vulnerability of a person with ID and their ecosystem, in other words, their family, and cultural and institutional environment, which can be a barrier or a facilitator. Identifying a child with an unusual developmental trajectory requires professionals to have a good understanding of psychomotor development. ID may be isolated but is very often intertwined with other neurodevelopmental disorders, including autism, motor or sensory difficulties (hearing, vision), serious sleep and eating disorders, and medical conditions such as epilepsy, as well as a wide variety of psychopathologic problems, including anxiety, depression, and emotional regulation disorders. There are many causes of ID. More than half of all cases are genetic in origin, and there are several hundreds of rare diseases about which little is known so far. The use of new genetic techniques (high-throughput sequencing) should reduce the number of people who are undiagnosed and give way to a comprehensive diagnostic approach based on clinical practice. A regular multidimensional evaluation of cognitive, educational, socioemotional, and adaptive skills throughout life provides a better understanding of how individuals with ID function and will contribute toward the planning of more appropriate strategies for learning, care, and support, leading to a better quality of life and participation in society.
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http://dx.doi.org/10.1016/B978-0-444-64148-9.00009-0DOI Listing
July 2021

Early-onset epileptic encephalopathy with migrating focal seizures associated with a FARS2 homozygous nonsense variant.

Epileptic Disord 2020 Jun;22(3):327-335

Paediatric Clinical Epileptology and Functional Neurology Department, Reference Center of rare epilepsies, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France.

Epilepsy of infancy with migrating focal seizures (EIMFS) is now a well-recognized early-onset syndrome included in the ILAE classification of the epilepsies. KCNT1 gain-of-function variants are identified in about half of patients. In the remaining cases, the underlying genetic component is far more heterogeneous with sporadic mutations occasionally reported in SCN1A, SCN2A, SLC12A5, TBC1D24, PLCB1, SLC25A22, and KCNQ2. Here, we report, for the first time, a homozygous deleterious variant in the FARS2 gene, identified using a 115-gene panel for monogenic epilepsies, in a patient with EIMFS. This boy was the second child born to healthy consanguineous parents. The first seizures occurred at six weeks of age. The patient rapidly developed severe epilepsy with focal discharges on EEG, migrating from one brain region to another, highly suggestive of EIMFS. At five months of age, he had daily multifocal clonic seizures and erratic myoclonic fits, which were not consistently related to spikes or spike-and-wave discharges. Neurological status was severely abnormal from onset and the patient died at 10 months of age from respiratory distress. Using the gene panel, a homozygous missense variant of FARS2 was identified, at Chr6 (GRCh37):g.5404829C>T, c.667C>T (NM_001318872.1), inherited from both parents, leading to an arginine-to-cysteine substitution, p.(Arg223Cys). FARS2 is a member of the mitochondrial aminoacyl tRNA transferase (ARS) enzymes. ARS variants are increasingly recognized causes of early-onset epileptic and neurodevelopmental encephalopathies, however, the associated epileptic phenotype is not completely described. This case shows that FARS2-related seizures can mimic EIMFS in the early stage of the disease. Furthermore, in the setting of migrating focal seizures of infancy, FARS2 should be considered as a further candidate gene, and increased lactate level and occurrence of refractory myoclonic seizures are possible key features to suspect FARS deficiency.
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http://dx.doi.org/10.1684/epd.2020.1168DOI Listing
June 2020

Prenatal exome sequencing in 65 fetuses with abnormality of the corpus callosum: contribution to further diagnostic delineation.

Genet Med 2020 11 22;22(11):1887-1891. Epub 2020 Jun 22.

Service de Génétique Clinique, CHU de Dijon, Dijon, France.

Purpose: Abnormality of the corpus callosum (AbnCC) is etiologically a heterogeneous condition and the prognosis in prenatally diagnosed cases is difficult to predict. The purpose of our research was to establish the diagnostic yield using chromosomal microarray (CMA) and exome sequencing (ES) in cases with prenatally diagnosed isolated (iAbnCC) and nonisolated AbnCC (niAbnCC).

Methods: CMA and prenatal trio ES (pES) were done on 65 fetuses with iAbnCC and niAbnCC. Only pathogenic gene variants known to be associated with AbnCC and/or intellectual disability were considered.

Results: pES results were available within a median of 21.5 days (9-53 days). A pathogenic single-nucleotide variant (SNV) was identified in 12 cases (18%) and a pathogenic CNV was identified in 3 cases (4.5%). Thus, the genetic etiology was determined in 23% of cases. In all diagnosed cases, the results provided sufficient information regarding the neurodevelopmental prognosis and helped the parents to make an informed decision regarding the outcome of the pregnancy.

Conclusion: Our results show the significant diagnostic and prognostic contribution of CMA and pES in cases with prenatally diagnosed AbnCC. Further prospective cohort studies with long-term follow-up of the born children will be needed to provide accurate prenatal counseling after a negative pES result.
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http://dx.doi.org/10.1038/s41436-020-0872-8DOI Listing
November 2020

Movement disorders in patients with alternating hemiplegia: "Soft" and "stiff" at the same time.

Neurology 2020 03 2;94(13):e1378-e1385. Epub 2020 Mar 2.

From Sleep Disorders and Functional Neurology (E.P., A.A.), Department of Paediatric Clinical Epileptology, University Hospitals of Lyon, member of the ERN EpiCARE; Service de Neurologie Pédiatrique (D.D., T.B.), Hôpital Trousseau, APHP, Paris; Centre d'Investigation Clinique (E.N., N.N.), CHU Montpellier; Department of Medical Genetics (G.L.), Centre de Biologie Est, Lyon University Hospital, Hospices Civils de Lyon, member of the ERN EpiCARE; Laboratoire de Génétique (F.R.), Groupe Hospitalier Lariboisière-Fernand Widal AP-HP, Paris; IGF (S.N.), Univ Montpellier, CNRS, INSERM; Département de Neuropédiatrie (C.D., A.R.), CHU Gui de Chauliac, Montpellier; Service de Neuropédiatrie et Handicaps (M.A.B.), Hôpital Gatien de Clocheville, CHU Tours, France; Pediatric Neurology Unit (M.C.N.), Cliniques Universitaires Saint-Luc, UCLouvain, Brussels, Belgium; Service de Neuropédiatrie (A.D.), CHU de Bicêtre, Kremlin-Bicêtre; Service de Neuropédiatrie (L.V.), CHU Lille; Service de Neurochirurgie Pédiatrique (M.B.), Hôpital Necker-Enfants Malades, APHP, Paris; Service de Neurologie Pédiatrique (C.I.), Hôpital Raymond Poincarré, AP-HP, Garches; Service de Neurophysiologie (C.G.), Hôpital Necker, AP-HP, Paris; Département de Pédiatrie (C.L.), CHU Limoges; Service de Neurologie Pédiatrique (M.M.), CHU Timone Enfants, Marseille; Centre de Référence "Déficiences Intellectuelles de Causes Rares" (V.D.P.), Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, Université de Lyon; and INSERM U 1051 (A.R.), Institut des Neurosciences de Montpellier, France.

Objective: To assess nonparoxysmal movement disorders in mutation-positive patients with alternating hemiplegia of childhood (AHC).

Methods: Twenty-eight patients underwent neurologic examination with particular focus on movement phenomenology by a specialist in movement disorders. Video recordings were reviewed by another movement disorders specialist and data were correlated with patients' characteristics.

Results: Ten patients were diagnosed with chorea, 16 with dystonia (nonparoxysmal), 4 with myoclonus, and 2 with ataxia. Nine patients had more than one movement disorder and 8 patients had none. The degree of movement disorder was moderate to severe in 12/28 patients. At inclusion, dystonic patients (n = 16) were older ( = 0.007) than nondystonic patients. Moreover, patients (n = 18) with dystonia or chorea, or both, had earlier disease onset ( = 0.042) and more severe neurologic impairment ( = 0.012), but this did not correlate with genotype. All patients presented with hypotonia, which was characterized as moderate or severe in 16/28. Patients with dystonia or chorea (n = 18) had more pronounced hypotonia ( = 0.011). Bradykinesia (n = 16) was associated with an early age at assessment ( < 0.01). Significant dysarthria was diagnosed in 11/25 cases. A history of acute neurologic deterioration and further regression of motor function, typically after a stressful event, was reported in 7 patients.

Conclusions: Despite the relatively limited number of patients and the cross-sectional nature of the study, this detailed categorization of movement disorders in patients with AHC offers valuable insight into their precise characterization. Further longitudinal studies on this topic are needed.
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http://dx.doi.org/10.1212/WNL.0000000000009175DOI Listing
March 2020

Novel truncating and missense variants extending the spectrum of EMC1-related phenotypes, causing autism spectrum disorder, severe global development delay and visual impairment.

Eur J Med Genet 2020 Jun 22;63(6):103897. Epub 2020 Feb 22.

Department of Genetics, Hospices Civils de Lyon, Groupement Hospitalier Est, France; Claude Bernard Lyon 1 University, France. Electronic address:

The EMC1 gene, located on 1p36.13, encodes the subunit 1 of the endoplasmic reticulum-membrane protein complex, a highly conserved and ubiquitous multiprotein transmembrane complex. Pathogenic monoallelic and biallelic variants in EMC1 in humans have been reported only in six families, causing isolated visual impairment or in association with psychomotor retardation and cerebellar atrophy. We report a ten-year-old boy, born to unrelated parents, with early-onset severe global development delay due to novel EMC1 biallelic pathogenic variants. A truncating variant, p.(Tyr378*) and a missense variant, p.(Phe953Ser), located in exon 11 and 23 of EMC1 gene respectively, have been found by reanalysis of exome sequencing data. The proband's phenotype included several signs that overlap with the phenotype of previously reported patients, associating severe global developmental delay, abnormal ophthalmological examination, and postnatal slow-down of the head circumference growth. Some distinguishing clinical signs were observed in comparison to patients from literature, such as autism spectrum disorder, absence of seizures, scoliosis or facial dysmorphic features, thus extending the spectrum of EMC1-related phenotypes. Similarly, brain MRI, performed at 2 years, showed normal cerebellar volume and structure, whereas cerebellar atrophy was described in literature. Moreover, difficulties of clinical differential diagnosis between EMC1-associated disease and other etiologies of global development delay support the importance of large-scale genetic investigations. Our diagnostic approach, through reanalysis of exome sequencing data, highlights the importance of reconsidering initial negative results for patients with a strong suspicion of genetic disease, and to update analytic pipelines in order to improve the diagnostic yield of exome sequencing.
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http://dx.doi.org/10.1016/j.ejmg.2020.103897DOI Listing
June 2020

Asparagine synthetase deficiency: A novel case with an unusual molecular mechanism.

Mol Genet Metab Rep 2019 Dec 1;21:100509. Epub 2019 Nov 1.

Service de Biochimie & Biologie Moléculaire, UF Maladies Héréditaires du Métabolisme, Hospices Civils de Lyon, F-69500 Bron, France.

We report the case of a girl with Asparagine synthetase deficiency, an autosomal recessive metabolic disorder characterized by severe microcephaly and epileptic encephalopathy secondary to pathogenic variants in the gene. Genetic explorations found a deletion of and a missense variant on the other allele detected respectively by array comparative genomic hybridization (CGH) and Sanger sequencing. Amino acid analysis provided a biochemical confirmation. Previous cases of Asparagine synthetase deficiency were diagnosed though exome Sequencing. The combination of several techniques (array CGH, sequencing, and biochemical analysis) improves the opportunity to provide accurate diagnosis.
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http://dx.doi.org/10.1016/j.ymgmr.2019.100509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6838931PMC
December 2019

Induced pluripotent stem cells (iPSCs) derived from a renpenning syndrome patient with c.459_462delAGAG mutation in PQBP1 (PEIi001-A).

Stem Cell Res 2019 12 15;41:101592. Epub 2019 Oct 15.

Host‑Pathogen Interactions, Paul-Ehrlich-Institut, Langen 63225, Germany; Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA. Electronic address:

The Renpenning syndrome spectrum is a rare X-linked mental retardation syndrome characterized by intellectual disability, microcephaly, low stature, lean body and hypogonadism. Mutations in the polyglutamine tract binding protein 1 (PQBP1) locus are causative for disease. Here, we describe the generation of an iPSC line from a patient mutated in the polar amino acid-rich domain of PQBP1 resulting in a C-terminal truncated protein (c.459_462 delAGAG, type p.R153fs193X).
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http://dx.doi.org/10.1016/j.scr.2019.101592DOI Listing
December 2019

Disruption of PHF21A causes syndromic intellectual disability with craniofacial anomalies, epilepsy, hypotonia, and neurobehavioral problems including autism.

Mol Autism 2019 22;10:35. Epub 2019 Oct 22.

21Department of Biology, Chungnam National University, Daejeon, Korea.

Background: has been associated with intellectual disability and craniofacial anomalies based on its deletion in the Potocki-Shaffer syndrome region at 11p11.2 and its disruption in three patients with balanced translocations. In addition, three patients with de novo truncating mutations in were reported recently. Here, we analyze genomic data from seven unrelated individuals with mutations in and provide detailed clinical descriptions, further expanding the phenotype associated with PHF21A haploinsufficiency.

Methods: Diagnostic trio whole exome sequencing, Sanger sequencing, use of GeneMatcher, targeted gene panel sequencing, and MiSeq sequencing techniques were used to identify and confirm variants. RT-qPCR was used to measure the normal expression pattern of in multiple human tissues including 13 different brain tissues. Protein-DNA modeling was performed to substantiate the pathogenicity of the missense mutation.

Results: We have identified seven heterozygous coding mutations, among which six are de novo (not maternal in one). Mutations include four frameshifts, one nonsense mutation in two patients, and one heterozygous missense mutation in the AT Hook domain, predicted to be deleterious and likely to cause loss of PHF21A function. We also found a new C-terminal domain composed of an intrinsically disordered region. This domain is truncated in six patients and thus likely to play an important role in the function of PHF21A, suggesting that haploinsufficiency is the likely underlying mechanism in the phenotype of seven patients. Our results extend the phenotypic spectrum of mutations by adding autism spectrum disorder, epilepsy, hypotonia, and neurobehavioral problems. Furthermore, is highly expressed in the human fetal brain, which is consistent with the neurodevelopmental phenotype.

Conclusion: Deleterious nonsense, frameshift, and missense mutations disrupting the AT Hook domain and/or an intrinsically disordered region in PHF21A were found to be associated with autism spectrum disorder, epilepsy, hypotonia, neurobehavioral problems, tapering fingers, clinodactyly, and syndactyly, in addition to intellectual disability and craniofacial anomalies. This suggests that is involved in autism spectrum disorder and intellectual disability, and its haploinsufficiency causes a diverse neurological phenotype.
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http://dx.doi.org/10.1186/s13229-019-0286-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6805429PMC
June 2020

KCNT1 epilepsy with migrating focal seizures shows a temporal sequence with poor outcome, high mortality and SUDEP.

Brain 2019 10;142(10):2996-3008

Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France.

Epilepsy of infancy with migrating focal seizures was first described in 1995. Fifteen years later, KCNT1 gene mutations were identified as the major disease-causing gene of this disease. Currently, the data on epilepsy of infancy with migrating focal seizures associated with KCNT1 mutations are heterogeneous and many questions remain unanswered including the prognosis and the long-term outcome especially regarding epilepsy, neurological and developmental status and the presence of microcephaly. The aim of this study was to assess data from patients with epilepsy in infancy with migrating focal seizures with KCNT1 mutations to refine the phenotype spectrum and the outcome. We used mind maps based on medical reports of children followed in the network of the French reference centre for rare epilepsies and we developed family surveys to assess the long-term outcome. Seventeen patients were included [age: median (25th-75th percentile): 4 (2-15) years, sex ratio: 1.4, length of follow-up: 4 (2-15) years]. Seventy-one per cent started at 6 (1-52) days with sporadic motor seizures (n = 12), increasing up to a stormy phase with long lasting migrating seizures at 57 (30-89) days. The others entered this stormy phase directly at 1 (1-23) day. Ten patients entered a consecutive phase at 1.3 (1-2.8) years where seizures persisted at least daily (n = 8), but presented different semiology: brief and hypertonic with a nocturnal (n = 6) and clustered (n = 6) aspects. Suppression interictal patterns were identified on the EEG in 71% of patients (n = 12) sometimes from the first EEG (n = 6). Three patients received quinidine without reported efficacy. Long-term outcome was poor with neurological sequelae and active epilepsy except for one patient who had an early and long-lasting seizure-free period. Extracerebral symptoms probably linked with KCNT1 mutation were present, including arteriovenous fistula, dilated cardiomyopathy and precocious puberty. Eight patients (47%) had died at 3 (1.5-15.4) years including three from suspected sudden unexpected death in epilepsy. Refining the electro-clinical characteristics and the temporal sequence of epilepsy in infancy with migrating focal seizures should help diagnosis of this epilepsy. A better knowledge of the outcome allows one to advise families and to define the appropriate follow-up and therapies. Extracerebral involvement should be investigated, in particular the cardiac system, as it may be involved in the high prevalence of sudden unexpected death in epilepsy in these cases.
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http://dx.doi.org/10.1093/brain/awz240DOI Listing
October 2019

Expanding the phenotypic spectrum of Allan-Herndon-Dudley syndrome in patients with SLC16A2 mutations.

Dev Med Child Neurol 2019 12 13;61(12):1439-1447. Epub 2019 Aug 13.

Centre de Compétence des Leucodystrophies et Leucoencéphalopathies de Cause Rare, Pôle Femme et Enfant, Hôpital Estaing, Centre Hospitalier Universitaire de Clermont-Ferrand, Clermont-Ferrand, France.

The aim of the study was to redefine the phenotype of Allan-Herndon-Dudley syndrome (AHDS), which is caused by mutations in the SLC16A2 gene that encodes the brain transporter of thyroid hormones. Clinical phenotypes, brain imaging, thyroid hormone profiles, and genetic data were compared to the existing literature. Twenty-four males aged 11 months to 29 years had a mutation in SLC16A2, including 12 novel mutations and five previously described mutations. Sixteen patients presented with profound developmental delay, three had severe intellectual disability with poor language and walking with an aid, four had moderate intellectual disability with language and walking abilities, and one had mild intellectual disability with hypotonia. Overall, eight had learned to walk, all had hypotonia, 17 had spasticity, 18 had dystonia, 12 had choreoathetosis, 19 had hypomyelination, and 10 had brain atrophy. Kyphoscoliosis (n=12), seizures (n=7), and pneumopathies (n=5) were the most severe complications. This study extends the phenotypic spectrum of AHDS to a mild intellectual disability with hypotonia. Developmental delay, hypotonia, hypomyelination, and thyroid hormone profile help to diagnose patients. Clinical course depends on initial severity, with stable acquisition after infancy; this may be adversely affected by neuro-orthopaedic, pulmonary, and epileptic complications. WHAT THIS PAPER ADDS: Mild intellectual disability is associated with SLC16A2 mutations. A thyroid hormone profile with a free T /T ratio higher than 0.75 can help diagnose patients. Patients with SLC16A2 mutations present a broad spectrum of neurological phenotypes that are also observed in other hypomyelinating disorders. Axial hypotonia is a consistent feature of Allan-Herndon-Dudley syndrome and leads to specific complications.
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http://dx.doi.org/10.1111/dmcn.14332DOI Listing
December 2019

Fetal and perinatal outcome associated with small cerebellar diameter based on second- or third-trimester ultrasonography.

Prenat Diagn 2019 06 29;39(7):536-543. Epub 2019 May 29.

Hospices Civils de Lyon, Department of Obstetrics and Gynecology, Hôpital Femme Mère Enfant, Université Claude Bernard, Lyon 1, Bron-, Lyon, 69500, France.

Objective: To examine the outcome of pregnancy with fetal transverse cerebellar diameter (TCD) below the fifth percentile based on routine second- or third-trimester ultrasonography.

Methods: We retrospectively analyzed the outcomes of 12 344 women according to TCD Z scores based on systematic second- or third-trimester ultrasound examination between 2007 and 2015. Information on major malformations, chromosomal anomalies, intrauterine or neonatal demise, and other abnormal findings were collected.

Results: In total, 408 fetuses with small prenatal TCD underwent clinical investigation; 160 major malformations were noted, consisting mainly of neurological or cardiac anomalies (39,2%%). Chromosomal anomalies were reported in 39 (9.5%) and intrauterine or neonatal demise in 41 cases (10%). Major malformations and chromosomal anomalies were found in 46.4% and 10% of fetuses with extremely small TCD (Z score < -2.5), respectively, 31.3% and 12.7% of fetuses with small TCD (Z score between -2.0 and -1.645), and 39.6 % and 7.7% of fetuses with subnormal TCD (Z score between -2.0 and -1.645). Intrauterine or neonatal demise was noted in 22%, 8.8%, and 4.8% of fetuses with extremely small, small, and subnormal TCD, respectively (P < .05). Among intrauterine growth-restricted fetuses, fetal demise or neonatal adverse outcome was reported in 75%, 81.8%, and 18.5%, respectively. Of all the fetuses, 2.2% were lost to follow-up.

Conclusion: A small cerebellar diameter below the fifth percentile is a relevant marker to detect associated anomalies during routine ultrasound examination in the second or third trimester. This is related to a high rate of fetal malformations, chromosomal anomalies, and genetic disorders, regardless of the severity of the cerebellar small size. Small TCD seems to be a prognostic factor for fetal growth restriction. Therefore, when facing a TCD below the fifth percentile, patients should be referred for further sonography and fetal karyotyping.
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http://dx.doi.org/10.1002/pd.5465DOI Listing
June 2019

[Disabled child. Orientation and management].

Rev Prat 2018 Oct;68(8):e327-e334

PU-PH, neuropédiatrie, CHU de Lyon - université Lyon 1, chef de service, service de neuropédiatrie, hôpital Femme-Mère-Enfant, 69677 Bron Cedex, France.

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October 2018

Mavoglurant in Fragile X Syndrome: Results of two open-label, extension trials in adults and adolescents.

Sci Rep 2018 11 19;8(1):16970. Epub 2018 Nov 19.

Neuroscience Development, Novartis Pharma AG, Basel, Switzerland.

Fragile X syndrome (FXS) is the most common monogenic cause of inherited intellectual and developmental disabilities. Mavoglurant, a selective metabotropic glutamate receptor subtype-5 antagonist, has shown positive neuronal and behavioral effects in preclinical studies, but failed to demonstrate any behavioral benefits in two 12-week, randomized, placebo-controlled, double-blind, phase IIb studies in adults and adolescents with FXS. Here we report the long-term safety (primary endpoint) and efficacy (secondary endpoint) results of the open-label extensions. Adolescent (n = 119, aged 12-19 years) and adult (n = 148, aged 18-45 years) participants received up to 100 mg bid mavoglurant for up to 34 months. Both extension studies were terminated prematurely due to lack of proven efficacy in the core studies. Mavoglurant was well tolerated with no new safety signal. Five percent of adults and 16.9 percent of adolescents discontinued treatment due to adverse events. Gradual and consistent behavioral improvements as measured by the ABC-C scale were observed, which were numerically superior to those seen in the placebo arm of the core studies. These two extension studies confirm the long-term safety of mavoglurant in FXS, but further investigations are required to determine whether and under which conditions the significant preclinical results obtained with mGluR5 inhibition can translate to humans.
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http://dx.doi.org/10.1038/s41598-018-34978-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6242849PMC
November 2018

Further delineation of the clinical spectrum of de novo TRIM8 truncating mutations.

Am J Med Genet A 2018 11 23;176(11):2470-2478. Epub 2018 Sep 23.

Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, Dijon, France.

De novo mutations of the TRIM8 gene, which codes for a tripartite motif protein, have been identified using whole exome sequencing (WES) in two patients with epileptic encephalopathy (EE), but these reports were not sufficient to conclude that TRIM8 was a novel gene responsible for EE. Here we report four additional patients presenting with EE and de novo truncating mutations of TRIM8 detected by WES, and give further details of the patient previously reported by the Epi4K consortium. Epilepsy of variable severity was diagnosed in children aged 2 months to 3.5 years of age. All patients had developmental delay of variable severity with no or very limited language, often associated with behavioral anomalies and unspecific facial features or MRI brain abnormalities. The phenotypic variability observed in these patients appeared related to the severity of the epilepsy. One patient presented pharmacoresistant EE with regression, recurrent infections and nephrotic syndrome, compatible with the brain and kidney expression of TRIM8. Interestingly, all mutations were located at the highly conserved C-terminus section of TRIM8. This collaborative study confirms that TRIM8 is a novel gene responsible for EE, possibly associated with nephrotic syndrome. This report brings new evidence on the pathogenicity of TRIM8 mutations and highlights the value of data-sharing to delineate the phenotypic characteristics and biological basis of extremely rare disorders.
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http://dx.doi.org/10.1002/ajmg.a.40357DOI Listing
November 2018

Electrical status epilepticus in sleep, a constitutive feature of Christianson syndrome?

Eur J Paediatr Neurol 2018 Nov 21;22(6):1124-1132. Epub 2018 Jul 21.

Department of Medical Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon 1 University, Lyon, France; INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Centre (CRNL), Lyon, France. Electronic address:

Christianson syndrome (CS) is a X-linked neurodevelopmental disorder, including severe intellectual disability (ID), progressive microcephaly, ataxia, autistic behaviour (ASD), near absent speech, and epilepsy. Electrical status epilepticus in sleep (ESES) has been reported in two patients. We describe five male patients from three unrelated families with Christianson syndrome caused by a pathogenic nucleotide variation or a copy-number variation involving SLC9A6. ESES was present in three out of the five patients in the critical age window between 4 and 8 years. All patients presented with severe intellectual disability, autistic features, and hyperactivity. Epilepsy onset occurred within the first two years of life. Seizures were of various types. In the two boys with a 20-years follow-up, epilepsy was drug-resistant during childhood, and became less active in early adolescence. Psychomotor regression was noted in two patients presenting with ESES. It was difficult to assess to what extent ESES could have contributed to the pathophysiological process, leading to regression of the already very limited communication skills. The two published case reports and our observation suggests that ESES could be a constitutive feature of Christianson syndrome, as it has already been shown for other Mendelian epileptic disorders, such as GRIN2A and CNKSR2-related developmental epileptic encephalopathies. Sleep EEG should be performed in patients with Christianson syndrome between 4 and 8 years of age. ESES occurring in the context of ID, ASD and severe speech delay, could be helpful to make a diagnosis of CS.
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http://dx.doi.org/10.1016/j.ejpn.2018.07.004DOI Listing
November 2018

Basal ganglia involvement in patients: The reason for patients very specific grasping?

Neuroimage Clin 2018 5;19:454-465. Epub 2018 Apr 5.

Psychiatric Neuroimaging Program, Department of Psychiatry, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.

The () gene was identified in 2002 as responsible for XLAG syndrome, a lissencephaly characterized by an almost complete absence of cortical GABAergic interneurons, and for milder forms of X-linked Intellectual Disability (ID) without apparent brain abnormalities. The most frequent mutation found in the gene, a duplication of 24 base pairs (c.429_452dup24) in exon 2, results in a recognizable syndrome in which patients present ID without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip, described as developmental Limb Kinetic Apraxia (LKA). In this study, we first present expression during human fetal brain development showing that it is strongly expressed in GABAergic neuronal progenitors during the second and third trimester of pregnancy. We show that although expression strongly decreases towards the end of gestation, it is still present after birth in some neurons of the basal ganglia, thalamus and cerebral cortex, suggesting that ARX also plays a role in more mature neuron functioning. Then, using morphometric brain MRI in 13 patients carrying c.429_452dup24 mutation and in 13 sex- and age-matched healthy controls, we show that patients have a significantly decreased volume of several brain structures including the striatum (and more specifically the caudate nucleus), hippocampus and thalamus as well as decreased precentral gyrus cortical thickness. We observe a significant correlation between caudate nucleus volume reduction and motor impairment severity quantified by kinematic parameter of precision grip. As basal ganglia are known to regulate sensorimotor processing and are involved in the control of precision gripping, the combined decrease in cortical thickness of primary motor cortex and basal ganglia volume in dup24 patients is very likely the anatomical substrate of this developmental form of LKA.
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http://dx.doi.org/10.1016/j.nicl.2018.04.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6029499PMC
January 2019

Characterization of two familial cases presenting with a syndromic specific learning disorder and carrying (17q;21q) unbalanced translocations.

Clin Case Rep 2018 May 9;6(5):827-834. Epub 2018 Mar 9.

Centre de référence des anomalies du développement Service de Génétique Hospices Civils de Lyon Bron France.

Chromosomal microarray (CMA) can detect pathogenic copy number variations in 15-20% of individuals with intellectual disability and in 10% of patients with autism spectrum disorders. The diagnostic rate in specific learning disorders (SLD) is unknown. Our study emphasizes the usefulness of CMA in the diagnostic workout assessment of familial SLD.
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http://dx.doi.org/10.1002/ccr3.1450DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5930267PMC
May 2018

The epilepsy phenotypic spectrum associated with a recurrent CUX2 variant.

Ann Neurol 2018 05 30;83(5):926-934. Epub 2018 Apr 30.

Department of Medical Genetics, Lyon University Hospital and GENDEV team CNRS UMR 5292, INSERM U1028, CRNL, and University Claude Bernard Lyon 1, GHE, Lyon, France.

Objective: Cut homeodomain transcription factor CUX2 plays an important role in dendrite branching, spine development, and synapse formation in layer II to III neurons of the cerebral cortex. We identify a recurrent de novo CUX2 p.Glu590Lys as a novel genetic cause for developmental and epileptic encephalopathy (DEE).

Methods: The de novo p.Glu590Lys variant was identified by whole-exome sequencing (n = 5) or targeted gene panel (n = 4). We performed electroclinical and imaging phenotyping on all patients.

Results: The cohort comprised 7 males and 2 females. Mean age at study was 13 years (0.5-21.0). Median age at seizure onset was 6 months (2 months to 9 years). Seizure types at onset were myoclonic, atypical absence with myoclonic components, and focal seizures. Epileptiform activity on electroencephalogram was seen in 8 cases: generalized polyspike-wave (6) or multifocal discharges (2). Seizures were drug resistant in 7 or controlled with valproate (2). Six patients had a DEE: myoclonic DEE (3), Lennox-Gastaut syndrome (2), and West syndrome (1). Two had a static encephalopathy and genetic generalized epilepsy, including absence epilepsy in 1. One infant had multifocal epilepsy. Eight had severe cognitive impairment, with autistic features in 6. The p.Glu590Lys variant affects a highly conserved glutamine residue in the CUT domain predicted to interfere with CUX2 binding to DNA targets during neuronal development.

Interpretation: Patients with CUX2 p.Glu590Lys display a distinctive phenotypic spectrum, which is predominantly generalized epilepsy, with infantile-onset myoclonic DEE at the severe end and generalized epilepsy with severe static developmental encephalopathy at the milder end of the spectrum. Ann Neurol 2018;83:926-934.
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http://dx.doi.org/10.1002/ana.25222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6021218PMC
May 2018

Further delineation of the duplication syndrome phenotype in 59 French male patients, with a particular focus on morphological and neurological features.

J Med Genet 2018 Jun 4;55(6):359-371. Epub 2018 Apr 4.

Service de Génétique Clinique, Hôpital Necker Enfants Malades, APHP, Paris, France.

The Xq28 duplication involving the gene ( duplication) has been mainly described in male patients with severe developmental delay (DD) associated with spasticity, stereotypic movements and recurrent infections. Nevertheless, only a few series have been published. We aimed to better describe the phenotype of this condition, with a focus on morphological and neurological features. Through a national collaborative study, we report a large French series of 59 affected males with interstitial duplication. Most of the patients (93%) shared similar facial features, which evolved with age (midface hypoplasia, narrow and prominent nasal bridge, thick lower lip, large prominent ears), thick hair, livedo of the limbs, tapered fingers, small feet and vasomotor troubles. Early hypotonia and global DD were constant, with 21% of patients unable to walk. In patients able to stand, lower limbs weakness and spasticity led to a singular standing habitus: flexion of the knees, broad-based stance with pseudo-ataxic gait. Scoliosis was frequent (53%), such as divergent strabismus (76%) and hypermetropia (54%), stereotypic movements (89%), without obvious social withdrawal and decreased pain sensitivity (78%). Most of the patients did not develop expressive language, 35% saying few words. Epilepsy was frequent (59%), with a mean onset around 7.4 years of age, and often (62%) drug-resistant. Other medical issues were frequent: constipation (78%), and recurrent infections (89%), mainly lung. We delineate the clinical phenotype of duplication syndrome in a large series of 59 males. Pulmonary hypertension appeared as a cause of early death in these patients, advocating its screening early in life.
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http://dx.doi.org/10.1136/jmedgenet-2017-104956DOI Listing
June 2018

Genetic Counselling Pitfall: Co-Occurrence of an 11.8-Mb Xp22 Duplication and an Xp21.2 Duplication Disrupting .

Mol Syndromol 2017 Nov 7;8(6):325-330. Epub 2017 Sep 7.

Hospices Civils de Lyon, Service de Génétique, CHU de Lyon, Lyon, France.

We report a 3-generation family in which 2 Xp copy number variations (CNVs) co-segregate. The proband presented with syndromic intellectual disability. The CNV had been revealed by conventional karyotyping, identifying a large Xp22 duplication causing an Xp functional disomy. Family studies found that this duplication was inherited from the proband's mother and was also present in one of his sisters. This sister had conventional karyotyping performed during pregnancy with a normal result. Postnatally, her child, the proband's nephew, presented with autism spectrum disorders. aCGH revealed a 339-kb duplication. Overall, the proband, his mother, and one of his sisters all harboured both CNVs, while his other sister and the 2 sons of each sister only carried the intragenic duplication. As seen in this family, we emphasise the importance of small CNV detection, the pathogenicity of exonic duplications in male carriers, and the difficulties for genetic counselling with the risk of double diagnosis in a single patient.
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http://dx.doi.org/10.1159/000479455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5701268PMC
November 2017

Drug development for neurodevelopmental disorders: lessons learned from fragile X syndrome.

Nat Rev Drug Discov 2018 04 8;17(4):280-299. Epub 2017 Dec 8.

Service de Génétique Médicale, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon 46, 1011 Lausanne and University of Lausanne, Switzerland.

Neurodevelopmental disorders such as fragile X syndrome (FXS) result in lifelong cognitive and behavioural deficits and represent a major public health burden. FXS is the most frequent monogenic form of intellectual disability and autism, and the underlying pathophysiology linked to its causal gene, FMR1, has been the focus of intense research. Key alterations in synaptic function thought to underlie this neurodevelopmental disorder have been characterized and rescued in animal models of FXS using genetic and pharmacological approaches. These robust preclinical findings have led to the implementation of the most comprehensive drug development programme undertaken thus far for a genetically defined neurodevelopmental disorder, including phase IIb trials of metabotropic glutamate receptor 5 (mGluR5) antagonists and a phase III trial of a GABA receptor agonist. However, none of the trials has been able to unambiguously demonstrate efficacy, and they have also highlighted the extent of the knowledge gaps in drug development for FXS and other neurodevelopmental disorders. In this Review, we examine potential issues in the previous studies and future directions for preclinical and clinical trials. FXS is at the forefront of efforts to develop drugs for neurodevelopmental disorders, and lessons learned in the process will also be important for such disorders.
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http://dx.doi.org/10.1038/nrd.2017.221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6904225PMC
April 2018

Outcome of isolated agenesis of the corpus callosum: A population-based prospective study.

Eur J Paediatr Neurol 2018 Jan 5;22(1):82-92. Epub 2017 Sep 5.

Université de Lyon, F-69008 Lyon, France; Radiologie pédiatrique et médecine fœtale, Hôpital Femme Mère Enfant, F-69677 Bron, France.

Objectives: Neurodevelopmental outcome of apparently isolated agenesis of the corpus callosum (ACC) remains a major concern with uncertain prognosis. Despite "normal" IQ reported in a majority of patients, the rates of learning disabilities and severe outcome (ranging from 0% to 20%) are not clearly established.

Methods: A large population-based series was investigated based on a longitudinal follow-up until school age, using Wechsler Intelligence scales at 3, 5, and 7 years.

Results: Fifty women were referred to a tertiary referral unit for an "apparently" isolated ACC confirmed by ultrasound, foetal MRI, and karyotyping or array CGH. Twelve pregnancies were terminated, one foetus died in utero, one pregnancy outcome was unknown, and 36 babies were born. Two were lost to follow-up. Thirty-four children could be classified into three groups. Group 1 comprised two children (6%) with severe intellectual disability (one Mowat-Wilson syndrome and one ASD). Group 2 comprised 10 children (29%) who had learning disabilities and borderline intellectual functioning (VIQ and/or PIQ scores >70 and <85); three patients had hypopituitarism with additional MRI anomalies revealed after birth. Group 3 comprised 22 children (65%) who had both VIQ and PIQ >85 (-1 SD) with a normal school level. Longitudinal follow-up revealed weaker PIQ in younger children which improved with age.

Conclusion: Our data indicate that intellectual ability is normal (IQ > 85) in approximately two thirds and borderline in just over a quarter of patients. However, a low risk of severe cognitive impairment exists, and this information should be shared with couples during prenatal counselling.
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http://dx.doi.org/10.1016/j.ejpn.2017.08.003DOI Listing
January 2018

Certainty of genuine treatment increases drug responses among intellectually disabled patients.

Neurology 2017 May 19;88(20):1912-1918. Epub 2017 Apr 19.

From the Department of Clinical Neuroscience (K.B.J., M.P., A.R.), Karolinska Institute, Sweden; Program in Placebo Studies (I.K., T.J.K.), BIDMC, Harvard Medical School; Department of Psychiatry (K.Y., R.L.G.), Massachusetts General Hospital, Boston; Institut des Sciences Cognitives (V.d.P., A.C.), Bron; Université Claude Bernard Lyon 1 (V.d.P., A.C.); Centre de Référence Déficiences Intellectuelles de Causes Rares (V.d.P., A.C.), Hôpital Femmes Mères Enfants, Hospices Civils de Lyon; and EPICIME-CIC1407/INSERM (A.C.), Bron, France.

Objective: To determine the placebo component of treatment responses in patients with intellectual disability (ID).

Methods: A statistical meta-analysis comparing bias-corrected effect sizes (Hedges ) of drug responses in open-label vs placebo-controlled clinical trials was performed, as these trial types represent different certainty of receiving genuine treatment (100% vs 50%). Studies in fragile X, Down, Prader-Willi, and Williams syndrome published before June 2015 were considered.

Results: Seventeen open-label trials (n = 261, 65% male; mean age 23.6 years; mean trial duration 38 weeks) and 22 placebo-controlled trials (n = 721, 62% male; mean age 17.1 years; mean trial duration 35 weeks) were included. The overall effect size from pre to post treatment in open-label studies was = 0.602 ( = 0.001). The effect of trial type was statistically significant ( = 0.001), and revealed higher effect sizes in studies with 100% likelihood of getting active drug, compared to both the drug and placebo arm of placebo-controlled trials. We thus provide evidence for genuine placebo effects, not explainable by natural history or regression toward the mean, among patients with ID.

Conclusions: Our data suggest that clinical trials in patients with severe cognitive deficits are influenced by the certainty of receiving genuine medication, and open-label design should thus not be used to evaluate the effect of pharmacologic treatments in ID, as the results will be biased by an enhanced placebo component.
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http://dx.doi.org/10.1212/WNL.0000000000003934DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5444309PMC
May 2017

Copy Number Variations Found in Patients with a Corpus Callosum Abnormality and Intellectual Disability.

J Pediatr 2017 06 8;185:160-166.e1. Epub 2017 Mar 8.

APHP, GH Pitié Salpêtrière, Department of genetics, unit of medical genetics, reference center for intellectual disabilities of rare causes, Paris, France; GRC Intellectual Disability and Autism, UPMC, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Inserm U 1127, CNRS UMR 7225, ICM, Paris, France; APHP, Hôpital Armand-Trousseau, Department of genetics, Division of clinical genetics, Paris, France.

Objective: To evaluate the role that chromosomal micro-rearrangements play in patients with both corpus callosum abnormality and intellectual disability, we analyzed copy number variations (CNVs) in patients with corpus callosum abnormality/intellectual disability STUDY DESIGN: We screened 149 patients with corpus callosum abnormality/intellectual disability using Illumina SNP arrays.

Results: In 20 patients (13%), we have identified at least 1 CNV that likely contributes to corpus callosum abnormality/intellectual disability phenotype. We confirmed that the most common rearrangement in corpus callosum abnormality/intellectual disability is inverted duplication with terminal deletion of the 8p chromosome (3.2%). In addition to the identification of known recurrent CNVs, such as deletions 6qter, 18q21 (including TCF4), 1q43q44, 17p13.3, 14q12, 3q13, 3p26, and 3q26 (including SOX2), our analysis allowed us to refine the 2 known critical regions associated with 8q21.1 deletion and 19p13.1 duplication relevant for corpus callosum abnormality; report a novel 10p12 deletion including ZEB1 recently implicated in corpus callosum abnormality with corneal dystrophy; and) report a novel pathogenic 7q36 duplication encompassing SHH. In addition, 66 variants of unknown significance were identified in 57 patients encompassed candidate genes.

Conclusions: Our results confirm the relevance of using microarray analysis as first line test in patients with corpus callosum abnormality/intellectual disability.
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http://dx.doi.org/10.1016/j.jpeds.2017.02.023DOI Listing
June 2017

Asperger syndrome and early-onset schizophrenia associated with a novel MECP2 deleterious missense variant.

Psychiatr Genet 2017 06;27(3):105-109

aClaude Bernard Lyon 1 University bInstitute of Cognitive Science, CNRS UMR 5304 cFrench National Reference Center for Rare Diseases with Intellectual Disability dReference Center on Learning Disabilities, Pediatric Functional Rehabilitation Department, Escale, Women Mothers and Children Hospital eDepartment of Child Psychiatry, Neurological Hospital fDepartment of Medical Genetics, Lyon University Hospital gCNRS UMR 5292, INSERM U1028, CNRL hDepartment of Child Psychiatry, Saint Jean de Dieu Hospital, Lyon, France.

Methyl-CpG-binding protein 2 (MECP2) deleterious variants, which are responsible for Rett syndrome in girls, are involved in a wide spectrum of developmental disabilities in males. A neuropsychiatric phenotype without intellectual disability is uncommon in patients with MECP2 deleterious variants. We report on two dizygotic twins with an MECP2-related psychiatric disorder without intellectual disability. Neuropsychological and psychiatric phenotype assessments were performed, and a genetic analysis was carried out. Both patients fulfilled the Pervasive Developmental Disorder criteria on Autism Diagnostic Observation Schedule and Asperger syndrome criteria on Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV). One patient developed early-onset schizophrenia (DSM-IV criteria) with two acute psychotic episodes, the latest one following corticosteroids and sodium valproate intake, with major hyperammonemia. A novel MECP2 gene transversion c.491 G>T [p.(Ser164Ile)] was found in both twins. Pathogenicity of this variant was considered on the basis of strong clinical and molecular data. The underlying molecular basis of neuropsychiatric disorders may have important consequences on genetic counseling and therapeutic strategies.
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http://dx.doi.org/10.1097/YPG.0000000000000165DOI Listing
June 2017
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