Bases moléculaires et physiopathologiques de syndromes avec anomalies du développement et déficience intellectuelle

Intellectual disability (ID) corresponds to abnormal intellectual performances and adaptive functions, beginning in childhood. It is estimated that 2-3% of individuals develop a ID, which represents a significant medical challenge since people with ID are frequently in situations of social dependence. Overall, a critical involvement of genetic factors in this disease is suspected. To date, several hundreds of genes are known to be responsible for ID. The ID is particularly characterized by extreme clinical and genetic heterogeneity, that made it resistant to conventional genetic studies. However, it is classicaly separated between syndromic ID, which may be clinically recognizable due to associated congenital anomalies; isolated ID, without disctinctive features.The objective of this thesis was to identify the molecular basis of ID by combining both approaches. The first is based on the systematic identification of chromosomal microrearrangements using array-CGH in a group of patients with ID, to constitute a posteriori homogeneous cohorts. The second is based on a cohort of patients with a clinical diagnosis of Shprintzen-Goldberg syndrome studied by high throughput sequencing.This thesis defines new clinical entities by identifying recurrent genetic variations between different patients including the description of two microdeletionnal syndromes, and two candidate genes to the ID. In addition, we identified the molecular basis for the Shprintzen-Goldberg syndrome by highlighting a mutational hotspot in the SKI gene.La déficience intellectuelle (DI) correspond à un défaut des performances intellectuelles et des fonctions adaptatives, débutant dans l’enfance. Il est estimé que 2-3% des individus développeront une DI, ce qui représente un enjeu médical important puisque les personnes avec DI sont fréquemment en situation de dépendance sociale. Dans l’ensemble, on estime majoritaire l’implication de facteurs génétique dans cette pathologie. A ce jour, plusieurs centaines de gènes sont connus pour être responsables de DI. La DI est notamment caractérisée par une extrême hétérogénéité clinique et génétique, qui l’a rendue résistante aux études génétiques classiques. Toutefois, on différencie les DI syndromiques, qui peuvent être cliniquement reconnaissables en raison des anomalies du développement qui lui est associées ; des DI isolées, sans signe distinctif.L’objectif de cette thèse est d’identifier des bases moléculaires de DI par la combinaison de deux approches. La première repose sur l’application systématique d’une recherche de microréarrangements chromosomiques par CGH-array dans un groupe de patients avec DI pour constituer a posteriori des groupes de patients homogènes. La seconde est basée sur une cohorte de patients avec DI syndromique homogène, porteurs d’un syndrome de Shprintzen-Goldberg de diagnostic clinique, étudiée par séquençage haut débit d’exome. Cette thèse définit de nouvelles entités cliniques par l’identification de variations génétiques récurrentes entre plusieurs patients comprenant la description de deux syndromes microdélétionnels, et de deux gènes candidats à la DI. De plus, nous avons pu identifier la base moléculaire du syndrome de Shprintzen-Goldberg par la mise en évidence d’un hotspot mutationnel du gène SKI

Signal Quality Monitoring Design for Galileo E5a and Galileo E1C signals

International audienceGalileo E1C, the pilot component of the E1 Open Service signal (CBOC(6,1,1/11) modulation), Galileo E5a and GPS L5 (BPSK(10) modulation) are signals that will be used by civil aviation receivers for pseudorange computation. To meet stringent requirements defined for civil aviation GNSS receivers, the characterization of distortions which could affect a GNSS signal in a hazardous way is required. In particular, expected signal distortions generated at payload level are described by Threat Models (TMs). Distortions incorporated in the TM are also called Evil WaveForm (EWF).These TMs, and their associated parameter ranges, referred to as Threat Space (TS), are powerful and necessary tools to design and test the performance of Signal Quality Monitor (SQM). The SQM is a mean to detect the presence of dangerous signal distortions and is necessary to protect users with high requirements in terms of integrity, accuracy, availability, and continuity (for example civil aviation users). Nowadays, this monitoring task is performed by GBAS and SBAS reference stations for GPS L1 C/A to warn the user in a timely manner. In this paper, SQMs for Galileo E1C and Galileo E5a will be designed and compared using a new representation introduced in [1]. Using this representation, different SQMs are compared and an optimized SQM is proposed to monitor signal distortions on Galileo E5a and Galileo E1C signals

Signal Quality Monitoring for New GNSS Signals

International audienceIn the context of GNSS signals and associated augmentation systems modernization, new modulations are envisaged. More precisely Galileo E1C, the pilot component of the E1 Open Service signal (CBOC(6,1,1/11) modulation), Galileo E5a and GPS L5 (BPSK(10) modulation) are signals that will be used by civil aviation airborne receivers for pseudorange computation. To meet stringent requirements defined for civil aviation GNSS receivers, the characterization of distortions which could affect a GNSS signal in a hazardous way is required. In particular, expected signal distortions generated at payload level are described by Threat Models (TM). Distortions incorporate in the TM are also called Evil Waveform (EWF). These TMs, and their associated parameter ranges, referred to as Threat Space (TS) are powerful and necessary tools to design and test the performance of Signal Quality Monitor (SQM). The SQM is a mean to detect the presence of dangerous signal distortions and is necessary to protect users with high requirements in terms of integrity, accuracy, availability, and continuity (for example civil aviation users). Nowadays, this monitoring task is performed by GBAS and SBAS reference station for GPS L1 C/A to warn the user in a timely manner. In this paper SQMs for Galileo E1C and Galileo E5a will be designed and compared by mean of an innovative representation inspired from [1]. From this representation, SQM performance is assessed based on the highest differential tracking error entailed by a signal distortion included in the TM and not detected by the SQM within allocated Pfa and Pmd.. It is noteworthy that performance of SQM is dependent on several parameters and in particular on the C/N0 at which the reference station is operating. One of the advantage of the proposed representation is that performances of the SQM can be assessed for different equivalent C/N0 from one figure. Using this representation, different SQMs are compared and an optimized SQM is proposed to monitor signal distortions on Galileo E5a and Galileo E1C signals

Rare deleterious mutations of HNRNP genes result in shared neurodevelopmental disorders

Familias de genes; Trastornos del desarrollo neurológico; HnRNPsFamílies genètiques; Trastorns del desenvolupament neurològic; HnRNPsGene families; Neurodevelopmental disorders; HnRNPsBackground With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype–phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations. Methods We tested our hypothesis by considering gene families that have multiple members with an enrichment of de novo variants among NDDs, as determined by previous meta-analyses. One of these gene families is the heterogeneous nuclear ribonucleoproteins (hnRNPs), which has 33 members, five of which have been recently identified as NDD genes (HNRNPK, HNRNPU, HNRNPH1, HNRNPH2, and HNRNPR) and two of which have significant enrichment in our previous meta-analysis of probands with NDDs (HNRNPU and SYNCRIP). Utilizing protein homology, mutation analyses, gene expression analyses, and phenotypic characterization, we provide evidence for variation in 12 HNRNP genes as candidates for NDDs. Seven are potentially novel while the remaining genes in the family likely do not significantly contribute to NDD risk. Results We report 119 new NDD cases (64 de novo variants) through sequencing and international collaborations and combined with published clinical case reports. We consider 235 cases with gene-disruptive single-nucleotide variants or indels and 15 cases with small copy number variants. Three hnRNP-encoding genes reach nominal or exome-wide significance for de novo variant enrichment, while nine are candidates for pathogenic mutations. Comparison of HNRNP gene expression shows a pattern consistent with a role in cerebral cortical development with enriched expression among radial glial progenitors. Clinical assessment of probands (n = 188–221) expands the phenotypes associated with HNRNP rare variants, and phenotypes associated with variation in the HNRNP genes distinguishes them as a subgroup of NDDs. Conclusions Overall, our novel approach of exploiting gene families in NDDs identifies new HNRNP-related disorders, expands the phenotypes of known HNRNP-related disorders, strongly implicates disruption of the hnRNPs as a whole in NDDs, and supports that NDD subtypes likely have shared molecular pathogenesis. To date, this is the first study to identify novel genetic disorders based on the presence of disorders in related genes. We also perform the first phenotypic analyses focusing on related genes. Finally, we show that radial glial expression of these genes is likely critical during neurodevelopment. This is important for diagnostics, as well as developing strategies to best study these genes for the development of therapeutics.This work was supported, in part, by the U.S. National Institutes of Health (R01MH101221) to E.E.E. Research reported in this publication was supported, in part, by the National Institute of Neurological Disorders and Stroke (NINDS) under award number K08NS092898, Jordan’s Guardian Angels, and the Brotman Baty Institute (to G.M.M.). M.I., A.C., and A.S. were supported by the G.E.N.E. (Genomic analysis Evaluation Network) Research Project founded by Progetti di Innovazione in Ambito Sanitario e Socio Sanitario (Bando EX decreto n.2713 28.02.2018) Regione Lombardia. D. L was supported by the German Research Foundation (DFG; LE 4223/1). B.B.A.d.V. and L.E.L.M.V. were supported by grants from the Dutch Organization for Health Research and Development (ZON-MW grants 917–86–319 and 912–12–109). M.E., O.G., and C.R. received funding from the Italian Ministry of Health (Project RC n. 2757328). I.T. is supported by generous donors to the Children’s Mercy Research Institute and the Genomic Answers for Kids program. K.X. is supported by the National Natural Science Foundation of China (NSFC: 8173000779) and the Science and Technology Major Project of Hunan Provincial Science and Technology Department (2018SK1030). M.A.G. was supported by the U.S. National Institutes of Health (T32HG000035). E.E.E. is an investigator of the Howard Hughes Medical Institute

PUF60 variants cause a syndrome of ID, short stature, microcephaly, coloboma, craniofacial, cardiac, renal and spinal features.

PUF60 encodes a nucleic acid-binding protein, a component of multimeric complexes regulating RNA splicing and transcription. In 2013, patients with microdeletions of chromosome 8q24.3 including PUF60 were found to have developmental delay, microcephaly, craniofacial, renal and cardiac defects. Very similar phenotypes have been described in six patients with variants in PUF60, suggesting that it underlies the syndrome. We report 12 additional patients with PUF60 variants who were ascertained using exome sequencing: six through the Deciphering Developmental Disorders Study and six through similar projects. Detailed phenotypic analysis of all patients was undertaken. All 12 patients had de novo heterozygous PUF60 variants on exome analysis, each confirmed by Sanger sequencing: four frameshift variants resulting in premature stop codons, three missense variants that clustered within the RNA recognition motif of PUF60 and five essential splice-site (ESS) variant. Analysis of cDNA from a fibroblast cell line derived from one of the patients with an ESS variants revealed aberrant splicing. The consistent feature was developmental delay and most patients had short stature. The phenotypic variability was striking; however, we observed similarities including spinal segmentation anomalies, congenital heart disease, ocular colobomata, hand anomalies and (in two patients) unilateral renal agenesis/horseshoe kidney. Characteristic facial features included micrognathia, a thin upper lip and long philtrum, narrow almond-shaped palpebral fissures, synophrys, flared eyebrows and facial hypertrichosis. Heterozygote loss-of-function variants in PUF60 cause a phenotype comprising growth/developmental delay and craniofacial, cardiac, renal, ocular and spinal anomalies, adding to disorders of human development resulting from aberrant RNA processing/spliceosomal function

Ten new cases further delineate the syndromic intellectual disability phenotype caused by mutations in DYRK1A

The dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) gene, located on chromosome 21q22.13 within the Down syndrome critical region, has been implicated in syndromic intellectual disability associated with Down syndrome and autism. DYRK1A has a critical role in brain growth and development primarily by regulating cell proliferation, neurogenesis, neuronal plasticity and survival. Several patients have been reported with chromosome 21 aberrations such as partial monosomy, involving multiple genes including DYRK1A. In addition, seven other individuals have been described with chromosomal rearrangements, intragenic deletions or truncating mutations that disrupt specifically DYRK1A. Most of these patients have microcephaly and all have significant intellectual disability. In the present study, we report 10 unrelated individuals with DYRK1A-associated intellectual disability (ID) who display a recurrent pattern of clinical manifestations including primary or acquired microcephaly, ID ranging from mild to severe, speech delay or absence, seizures, autism, motor delay, deep-set eyes, poor feeding and poor weight gain. We identified unique truncating and non-synonymous mutations (three nonsense, four frameshift and two missense) in DYRK1A in nine patients and a large chromosomal deletion that encompassed DYRK1A in one patient. On the basis of increasing identification of mutations in DYRK1A, we suggest that this gene be considered potentially causative in patients presenting with ID, primary or acquired microcephaly, feeding problems and absent or delayed speech with or without seizures

Studies on the Cobalt Deficiency in Ruminants (III) : Effects of Thiamine, Glucose and Cobalamin Injection on the Metabolism of Cobalt-deficient Sheep

International audienceN-terminal acetylation is a common protein modification in eukaryotes associated with numerous cellular processes. Inherited mutations in NAA10, encoding the catalytic subunit of the major N-terminal acetylation complex NatA have been associated with diverse, syndromic X-linked recessive disorders, whereas de novo missense mutations have been reported in one male and one female individual with severe intellectual disability but otherwise unspecific phenotypes. Thus, the full genetic and clinical spectrum of NAA10 deficiency is yet to be delineated. We identified three different novel and one known missense mutation in NAA10, de novo in 11 females, and due to maternal germ line mosaicism in another girl and her more severely affected and deceased brother. In vitro enzymatic assays for the novel, recurrent mutations p.(Arg83Cys) and p.(Phe128Leu) revealed reduced catalytic activity. X-inactivation was random in five females. The core phenotype of X-linked NAA10-related N-terminal-acetyltransferase deficiency in both males and females includes developmental delay, severe intellectual disability, postnatal growth failure with severe microcephaly, and skeletal or cardiac anomalies. Genotype–phenotype correlations within and between both genders are complex and may include various factors such as location and nature of mutations, enzymatic stability and activity, and X-inactivation in females

Fifteen years of research on oral–facial–digital syndromes: from 1 to 16 causal genes

Oral–facial–digital syndromes (OFDS) gather rare genetic disorders characterised by facial, oral and digital abnormalities associated with a wide range of additional features (polycystic kidney disease, cerebral malformations and several others) to delineate a growing list of OFDS subtypes. The most frequent, OFD type I, is caused by a heterozygous mutation in the OFD1 gene encoding a centrosomal protein. The wide clinical heterogeneity of OFDS suggests the involvement of other ciliary genes. For 15 years, we have aimed to identify the molecular bases of OFDS. This effort has been greatly helped by the recent development of whole-exome sequencing (WES). Here, we present all our published and unpublished results for WES in 24 cases with OFDS. We identified causal variants in five new genes (C2CD3, TMEM107, INTU, KIAA0753 and IFT57) and related the clinical spectrum of four genes in other ciliopathies (C5orf42, TMEM138, TMEM231 and WDPCP) to OFDS. Mutations were also detected in two genes previously implicated in OFDS. Functional studies revealed the involvement of centriole elongation, transition zone and intraflagellar transport defects in OFDS, thus characterising three ciliary protein modules: the complex KIAA0753-FOPNL-OFD1, a regulator of centriole elongation; the Meckel-Gruber syndrome module, a major component of the transition zone; and the CPLANE complex necessary for IFT-A assembly. OFDS now appear to be a distinct subgroup of ciliopathies with wide heterogeneity, which makes the initial classification obsolete. A clinical classification restricted to the three frequent/well-delineated subtypes could be proposed, and for patients who do not fit one of these three main subtypes, a further classification could be based on the genotype

Clinical reappraisal of SHORT syndrome with PIK3R1 mutations: towards recommendation for molecular testing and management

International audienceSHORT syndrome has historically been defined by its acronym: short stature (S), hyperextensibility of joints and/or inguinal hernia (H), ocular depression (O), Rieger abnormality (R) and teething delay (T). More recently several research groups have identified PIK3R1 mutations as responsible for SHORT syndrome. Knowledge of the molecular etiology of SHORT syndrome has permitted a reassessment of the clinical phenotype. The detailed phenotypes of 32 individuals with SHORT syndrome and PIK3R1 mutation, including eight newly ascertained individuals, were studied to fully define the syndrome and the indications for PIK3R1 testing. The major features described in the SHORT acronym were not universally seen and only half (52%) had 4 or more of the classic features. The commonly observed clinical features of SHORT syndrome seen in the cohort included IUGR \textless 10(th) percentile, postnatal growth restriction, lipoatrophy and the characteristic facial gestalt. Anterior chamber defects and insulin resistance or diabetes were also observed but were not as prevalent. The less specific, or minor features of SHORT syndrome include teething delay, thin wrinkled skin, speech delay, sensorineural deafness, hyperextensibility of joints and inguinal hernia. Given the high risk of diabetes mellitus, regular monitoring of glucose metabolism is warranted. An echocardiogram, ophthalmological and hearing assessments are also recommended

De novo TBR1 variants cause a neurocognitive phenotype with ID and autistic traits:report of 25 new individuals and review of the literature

TBR1, a T-box transcription factor expressed in the cerebral cortex, regulates the expression of several candidate genes for autism spectrum disorders (ASD). Although TBR1 has been reported as a high-confidence risk gene for ASD and intellectual disability (ID) in functional and clinical reports since 2011, TBR1 has only recently been recorded as a human disease gene in the OMIM database. Currently, the neurodevelopmental disorders and structural brain anomalies associated with TBR1 variants are not well characterized. Through international data sharing, we collected data from 25 unreported individuals and compared them with data from the literature. We evaluated structural brain anomalies in seven individuals by analysis of MRI images, and compared these with anomalies observed in TBR1 mutant mice. The phenotype included ID in all individuals, associated to autistic traits in 76% of them. No recognizable facial phenotype could be identified. MRI analysis revealed a reduction of the anterior commissure and suggested new features including dysplastic hippocampus and subtle neocortical dysgenesis. This report supports the role of TBR1 in ID associated with autistic traits and suggests new structural brain malformations in humans. We hope this work will help geneticists to interpret TBR1 variants and diagnose ASD probands