48 research outputs found
Exploring thienothiadiazine dioxides as isosteric analogues of benzo-and pyridothiadiazine dioxides in the search of new AMPA and kainate receptor positive allosteric modulators
peer reviewedThe synthesis and biological evaluation on AMPA and kainate receptors of new examples of 3,4-dihydro-2H-1,2,4-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxides is described. The introduction of a cyclopropyl chain instead of an ethyl chain at the 4-position of the thiadiazine ring was found to dramatically improve the potentiator activity on AMPA receptors, with compound 32 (BPAM395) expressing in vitro activity on AMPARs (EC2x = 0.24 ÎŒM) close to that of the reference 4-cyclopropyl-substituted benzothiadiazine dioxide 10 (BPAM344). Interestingly, the 4-allyl-substituted thienothiadiazine dioxide 27 (BPAM307) emerged as the most promising compound on kainate receptors being a more effective potentiator than the 4-cyclopropyl-substituted thienothiadiazine dioxide 32 and supporting the view that the 4-allyl substitution of the thiadiazine ring could be more favorable than the 4-cyclopropyl substitution to induce marked activity on kainate receptors versus AMPA receptors. The thieno-analogue 36 (BPAM279) of the clinically tested S18986 (11) was selected for in vivo evaluation in mice as a cognitive enhancer due to a safer profile than 32 after massive per os drug administration. Compound 36 was found to increase the cognition performance in mice at low doses (1 mg/kg) per os suggesting that the compound was well absorbed after oral administration and able to reach the central nervous system. Finally, compound 32 was selected for co-crystallization with the GluA2-LBD (L504Y,N775S) and glutamate to examine the binding mode of thienothiadiazine dioxides within the allosteric binding site of the AMPA receptor. At the allosteric site, this compound established similar interactions as the previously reported BTD-type AMPA receptor modulators
Genetic, Phenotypic, and Interferon Biomarker Status in ADAR1-Related Neurological Disease
International audienceWe investigated the genetic, phenotypic, and interferon status of 46 patients from 37 families with neurological disease due to mutations in ADAR1. The clinicoradiological phenotype encompassed a spectrum of AicardiâGoutiĂšres syndrome, isolated bilateral striatal necrosis, spastic paraparesis with normal neuroimaging, a progressive spastic dystonic motor disorder, and adult-onset psychological difficulties with intracranial calcification. Homozygous missense mutations were recorded in five families. We observed a p.Pro193Ala variant in the heterozygous state in 22 of 23 families with compound heterozygous mutations. We also ascertained 11 cases from nine families with a p.Gly1007Arg dominant-negative mutation, which occurred de novo in four patients, and was inherited in three families in association with marked phenotypic variability. In 50 of 52 samples from 34 patients, we identified a marked upregulation of type I interferon-stimulated gene transcripts in peripheral blood, with a median interferon score of 16.99 (interquartile range [IQR]: 10.64â25.71) compared with controls (median: 0.93, IQR: 0.57â1.30). Thus, mutations in ADAR1 are associated with a variety of clinically distinct neurological phenotypes presenting from early infancy to adulthood, inherited either as an autosomal recessive or dominant trait. Testing for an interferon signature in blood represents a useful biomarker in this context
A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing
Purpose
Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the âClinVar low-hanging fruitâ reanalysis, reasons for the failure of previous analyses, and lessons learned.
Methods
Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted.
Results
We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency).
Conclusion
The âClinVar low-hanging fruitâ analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock
Unusual clinical description of adult with Timothy syndrome, carrier of a new heterozygote mutation of CACNA1C
International audienceCANAC1C encodes for the main cardiac L-type calcium channel and mutations on it lead to a prolonged QT interval in Timothy Syndrome (TS). We provide a new de novo constitutional heterozygote missense variation in CACNA1C in a living adult woman, also carrier of the known c.2146-1G>C heterozygous variation of PKP2 inherited from her father. To our knowledge, this patient is the first to have the two variations in these genes. Theses clinical and molecular findings expand the clinical and molecular spectrum of TS and show the interest of next generation sequencing or whole exome sequencing in rare disorders, atypical or novel phenotype
HALOGENATION OF ETHANOL EXTRACT FROM PAEONIA SUFFRUTICOSA: EXPLORING PROMISING PATHWAYS FOR ANTI-SARS-COV-2 MEDICATION DEVELOPMENT
peer reviewedThe COVID-19 pandemic is now considered as an established and ongoing health issue according to the World Health Organization, presenting challenges worldwide despite available pharmaceutical interventions. In response to the pandemic, the Chinese government has proposed the use of Traditional Chinese Medicine (TCM) as a complementary approach to conventional treatments. TCM, deeply rooted in Asian healthcare, has gathered interest for its potential application in Western countries.
The present study focuses on preliminary investigations of halogenation processes applied to the ethanol extract obtained from Paeonia suffruticosa, a traditional Chinese plant, with the aim of enhancing its biological activity, particularly against SARS-CoV-2. Before achieving hemisynthesis on the crude extract, quercetin was choosen to find the optimal reaction conditions of the halogenation step, considering its presence in Paeonia suffruticosa, its abundance and cost-effectiveness. Various halogenation methods were evaluated, including the use of N-bromosuccinimide and an environmentally friendly (green) approach using sodium bromide and hydrogen peroxide. Both methods yielded promising results after LC-MS monitoring.
The green methodology was then used on the Paeonia suffruticosa ethanol extract, successfully generating brominated derivatives, such as dibromopaeonol and dibromooxypaeoniflorin. In conclusion, this preliminary study highlights the potential of halogenation processes to modify the ethanol extract from Paeonia suffruticosa and potentially enhance its anti-SARS-CoV-2 properties. These findings provide insights into the potential interest of TCM in the development of new lead compounds to fight the ongoing global COVID-19 pandemic.
Further investigations are however needed to validate these results and explore other promising late-stage functionalization strategies, using innovative green synthetic approaches
Phenotypic and genotypic characterization of 1q21.1 copy number variants: A report of 34 new individuals and literature review
Recurrent 1q21.1 copy number variants (CNVs) have been associated with a wide spectrum of clinical features, ranging from normal phenotype to moderate intellectual disability, with congenital anomalies and dysmorphic features. They are often inherited from unaffected parents and the pathogenicity is difficult to assess. We describe the phenotypic and genotypic data for 34 probands carrying CNVs in the 1q21.1 chromosome region (24 duplications, 8 deletions and 2 triplications). We also reviewed 89 duplications, 114 deletions and 5 triplications described in the literature, at variable 1q21.1 locations. We aimed to identify the most highly associated clinical features to determine the phenotypic expression in affected individuals. Developmental delay or learning disabilities and neuropsychiatric disorders were common in patients with deletions, duplications and triplications of 1q21.1. Mild dysmorphic features common in these CNVs include a prominent forehead, widely spaced eyes and a broad nose. The CNVs were mostly inherited from apparently unaffected parents. Almost half of the CNVs were distal, overlapping with a common minimal region of 1.2âMb. We delineated the clinical implications of 1q21.1 CNVs and confirmed that these CNVs are likely pathogenic, although subject to incomplete penetrance and variable expressivity. Longâterm followâup should be performed to each newly diagnosed case, and prenatal genetic counseling cautiously discussed, as it remains difficult to predict the phenotype in the event of an antenatal diagnosis
Caractérisation phénotypique et génotypique des réarrangements chromosomiques en 1q21.1: description d'une nouvelle cohorte de 34 patients et revue de la littérature
International audienc
P040 : TANC2 : un nouveau gÚne responsable de troubles neuro développementaux ?
National audienceDes Ă©tudes dâexome de larges cohortes de patients avec phĂ©notype caractĂ©risĂ© ont fortement contribuĂ© Ă l'identification degĂšnes candidats dans les troubles neuro dĂ©veloppementaux (TND) et Ă la caractĂ©risation de nouveaux syndromes avecdĂ©ficience intellectuelle (DI). Plusieurs de ces gĂšnes codent pour des protĂ©ines dâĂ©chaffaudage jouant un rĂŽle critique dans laneurotransmission glutamatĂ©rgique, organisant la composition post-synaptique des complexes de rĂ©cepteur glutamate et jouantun rĂŽle clĂ© au niveau des synapses ainsi que sur la plasticitĂ© neuronale. Parmi ceux-ci, le gĂšne TANC2 (Tetratricopeptiderepeat-, Ankyrin repeat-, and coiled-coil-containing protein 2, OMIM 615047) est un possible gĂšne candidat de TND avec desvariations faux sens identifiĂ©es dans le spectre phĂ©notypique des TND Ă savoir DI isolĂ©e, trouble du spectre autistique etschizophrĂ©nie. RĂ©cemment, l'analyse in silico de la famille de protĂ©ines TANC a conduit Ă prĂ©ciser leurs interactions et Ă comprendre les consĂ©quences neurobiologiques possibles de leur perturbation. Nous rapportons un frĂšre et une sĆurprĂ©sentant tous les deux un syndrome de Rett atypique et porteurs de la mĂȘme dĂ©lĂ©tion intragĂ©nique de TANC2, identifiĂ©e parCGHarray, non retrouvĂ©es chez les parents asymptomatiques. Par ailleurs, l'Ă©tude molĂ©culaire des gĂšnes impliquĂ©s dans lesencĂ©phalopathies Ă©pileptiques est nĂ©gatives dans la limite des techniques utilisĂ©es. Cette observation Ă©voque un mosaĂŻscismegerminal parental et la possible implication de TANC2 dans le phĂ©notype observĂ©. Lâanalyse des transcrits dans le sangpĂ©riphĂ©rique chez les deux patients comparĂ©s aux parents a permis dâidentifier un transcrit mutant emportant les exons 2 Ă 7 deTANC2, avec des Ă©tudes in silico indiquant une protĂ©ine tronquĂ©e de 290 acides aminĂ©s sans dĂ©calage du cadre de lecture.Dâautre part, lâĂ©tude dâexpression du transcrit TANC2 indique une double expression avec contribution non altĂ©rĂ©e du transcritsauvage chez ces 2 patients. Le mĂ©canisme suggĂ©rĂ© est une perte de fonction par effet dominant nĂ©gatif. Lâensemble de cesĂ©lĂ©ments est en faveur de lâimplication du gĂšne TANC2 dans les TND
Loss of Methylation at GNAS Exon A/B Is Associated With Increased Intrauterine Growth
International audienceGNAS is one of few genetic loci that undergo allelic-specific methylation resulting in the parent-specific expression of at least four different transcripts. Due to monoallelic expression, heterozygous GNAS mutations affecting either paternally or maternally derived transcripts cause different forms of pseudohypoparathyroidism (PHP), including autosomal-dominant PHP type Ib (AD-PHP1B) associated with loss of methylation (LOM) at exon A/B alone or sporadic PHP1B (sporPHP1B) associated with broad GNAS methylation changes. Similar to effects other imprinted genes have on early development, we recently observed severe intrauterine growth retardation in newborns, later diagnosed with pseudopseudohypoparathyroidism (PPHP) because of paternal GNAS loss-of-function mutations
Identification par sĂ©quençage du gĂ©nome entier dâune inversion de 140 Kb dans le locus GNAS impliquant NPELP1 et lâexon 1 du gĂšne XLas dans une famille prĂ©sentant une pseudohypoparathyroĂŻdie de type Ib autosomique dominante (AD-PHP1b)
International audienceLe locus GNAS code pour la sous-unitĂ© alpha de la protĂ©ine G stimulatrice (Gsα) et des transcrits supplĂ©mentaires soumis Ă lâempreinte. La pseudohypoparathyroĂŻdie de type 1b (PHP1b) est caractĂ©risĂ©e par une rĂ©sistance rĂ©nale Ă la PTH (et parfois une rĂ©sistance modĂ©rĂ©e Ă la TSH), qui survient gĂ©nĂ©ralement en l'absence dâautres caractĂ©ristiques de l'ostĂ©odystrophie hĂ©rĂ©ditaire d'Albright. La PHP1b est causĂ©e par des modifications Ă©pigĂ©nĂ©tiques au niveau d'une ou plusieurs rĂ©gions diffĂ©rentiellement mĂ©thylĂ©es (DMR) dans le locus GNAS. La cause gĂ©nĂ©tique la plus frĂ©quente de PHP1b autosomique dominante (AD-PHP1b) est la dĂ©lĂ©tion du gĂšne STX16 sur lâallĂšle maternel, qui conduit Ă une perte isolĂ©e de la mĂ©thylation (LOM) du DMR A/B. D'autres mĂ©canismes molĂ©culaires plus rares sont dĂ©crits, en particulier des anomalies du nombre de copies (dĂ©lĂ©tion/duplication) englobant un ou plusieurs DMR (NEPS55, NESPAS, XLαs).Nous avons Ă©tudiĂ© une famille avec deux membres atteints, le cas index et sa sĆur, prĂ©sentant un phĂ©notype typique de PHP1b. Un sĂ©quençage Sanger et une analyse par MS-MLPA du locus GNAS ont Ă©tĂ© rĂ©alisĂ©s pour les deux enfants et leurs parents. Un sĂ©quençage du gĂ©nome entier (WGS) a Ă©tĂ© rĂ©alisĂ©e pour le cas index: la prĂ©paration de la libraire a utilisĂ© le kit NEBNext, le sĂ©quençage a Ă©tĂ© effectuĂ© sur une plateforme Illumina, les sĂ©quences ont Ă©tĂ© alignĂ©es au gĂ©nome humain de rĂ©fĂ©rence GRCh38 et les donnĂ©es ont Ă©tĂ© traitĂ©es en utilisant le pipeline GATK. L'inversion a Ă©tĂ© confirmĂ©e par une analyse Sanger et par une analyse PCR de l'ADN gĂ©nomique en utilisant des amorces conçues pour amplifier spĂ©cifiquement les deux points de cassure.Le sĂ©quençage Sanger ne retrouvait pas de mutation dans le gĂšne GNAS. L'analyse par MS-MLPA nâa pas Ă©tĂ© mis en Ă©vidence dâanomalies du nombre de copies dans le locus GNAS mais a rĂ©vĂ©lĂ© chez le cas index et sa sĆur une LOM complĂšte au DMR A/B, une LOM partielle au DMR XLαs (25%) et une mĂ©thylation normale sur les autres DMRs AS et NESP. La mĂ©thylation Ă©tait normale pour les parents. Le WGS a rĂ©vĂ©lĂ© une inversion paracentrique de 140 kb avec comme points de cassure en 5 â: chr20: 58714222 (intron NPEPL1) et en 3âchr20: 58854618 (exon 1 XLαs). Ces points de cassure ont Ă©tĂ© confirmĂ©s par analyse Sanger pour les deux patients. Des amplicons ont Ă©tĂ© obtenus pour le cas index, sa sĆur et sa mĂšre, alors qu'aucun produit de PCR n'a Ă©tĂ© gĂ©nĂ©rĂ© pour l'ADN du pĂšre.Nous avons dĂ©tectĂ© dans une famille avec AD-PHP1b un nouveau rĂ©arrangement par WGS: une inversion en 20q13.3 qui inclut la rĂ©gion situĂ©e entre NPELP1 et XLαs. Ă notre connaissance, une seule inversion a Ă©tĂ© dĂ©crite dans AD-PHP1b, qui comprenait l'intĂ©gralitĂ© du DMR A/B et du gĂšne GNAS. Ces rĂ©sultats font suspecter la prĂ©sence dâun nouveau centre dâempreinte dans la rĂ©gion inversĂ©e. Des Ă©tudes complĂ©mentaires sont nĂ©cessaires pour vĂ©rifier cette hypothĂšse