Julien Thevenon

Julien Thevenon
University of Grenoble · Genetics

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208
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Publications

Publications (208)
Article
Prenatal exome sequencing could be complex because of limited phenotypical data compared to postnatal/portmortem phenotype in fetuses affected by multiple congenital abnormalities (MCA). Here, we investigated limits of prenatal phenotype for ES interpretation thanks to a blindly reanalysis of postmortem ES data using prenatal data only in fetuses a...
Article
Unique or multiple congenital facial skin polyps are features of several rare syndromes, from the most well‐known Pai syndrome (PS), to the less recognized oculoauriculofrontonasal syndrome (OAFNS), encephalocraniocutaneous lipomatosis (ECCL), or Sakoda complex (SC). We set up a research project aiming to identify the molecular bases of PS. We revi...
Article
BRD4 is part of a multiprotein complex involved in loading the cohesin complex onto DNA, a fundamental process required for cohesin‐mediated loop extrusion and formation of Topologically Associating Domains. Pathogenic variations in this complex have been associated with a growing number of syndromes, collectively known as cohesinopathies, the most...
Preprint
Purpose: Exome sequencing has a diagnostic yield ranging from 25% to 70% in rare diseases and regularly implicates genes in novel disorders. Prospective data reanalysis has demonstrated strong efficacy in improving diagnosis, but poses organizational difficulties for clinical laboratories. We applied a reanalysis strategy based on intensive prospec...
Article
Full-text available
Purpose Retrospective interpretation of sequenced data in light of the current literature is a major concern of the field. Such reinterpretation is manual and both human resources and variable operating procedures are the main bottlenecks. Methods Genome Alert! method automatically reports changes with potential clinical significance in variant cl...
Article
Auriculocondylar syndrome (ACS) is a rare craniofacial disorder characterized by mandibular hypoplasia and an auricular defect at the junction between the lobe and helix, known as a "Question Mark Ear" (QME). Several additional features, originating from the first and second branchial arches and other tissues, have also been reported. ACS is geneti...
Article
It has been estimated that Copy Number Variants (CNVs) account for 10%–20% of patients affected by Developmental Disorder (DD)/Intellectual Disability (ID). Although array comparative genomic hybridization (array‐CGH) represents the gold‐standard for the detection of genomic imbalances, common Agilent array‐CGH 4 × 180 kb arrays fail to detect CNVs...
Article
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Objective: Epilepsy is common in patients with PIGN diseases due to biallelic variants; however, limited epilepsy phenotyping data have been reported. We describe the epileptology of PIGN encephalopathy. Methods: We recruited patients with epilepsy due to biallelic PIGN variants and obtained clinical data regarding age at seizure onset/offset an...
Article
Background The EPIGENE network was created in 2014 by four multidisciplinary teams composed of geneticists, pediatric neurologists and neurologists specialized in epileptology and neurophysiology. The ambition of the network was to harmonize and improve the diagnostic strategy of Mendelian epileptic disorders using next-generation sequencing, in Fr...
Article
Full-text available
Considering that some Inherited Metabolic Disorders (IMDs) can be diagnosed in patients with no distinctive clinical features of IMDs, we aimed to evaluate the power of exome sequencing (ES) to diagnose IMDs within a cohort of 547 patients with unspecific developmental disorders (DD). IMDs were diagnosed in 12% of individuals with causative diagnos...
Article
Purpose Biallelic loss-of-function variants in ST3GAL5 cause GM3 synthase deficiency (GM3SD) responsible for Amish infantile epilepsy syndrome. All Amish patients carry the homozygous p.(Arg288Ter) variant arising from a founder effect. To date only 10 patients from 4 non-Amish families have been reported. Thus, the phenotypical spectrum of GM3SD d...
Preprint
Full-text available
Purpose: Despite exome (ES) or genome sequencing (GS) availability, chromosomal microarray (CMA) remains the first-line diagnostic tests in most rare disorders diagnostic work-up, looking for Copy-number variations (CNV), with a diagnostic yield of 10-20%. The question of the equivalence of CMA and ES in CNV calling is an organisational and economi...
Article
Aminoacyl-tRNA synthetases (aaRS) are ubiquitously expressed enzymes responsible for ligating amino acids to their cognate tRNA molecules through an aminoacylation reaction. The resulting aminoacyl-tRNA is delivered to ribosome elongation factors to participate in protein synthesis. Seryl-tRNA synthetase (SARS1) is one of the cytosolic aaRSs and ca...
Article
DYRK1A syndrome is among the most frequent monogenic forms of intellectual disability (ID). We refined the molecular and clinical description of this disorder and developed tools to improve interpretation of missense variants, which remains a major challenge in human genetics. We reported clinical and molecular data for 50 individuals with ID harbo...
Article
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Background: In France, the Ministry of Health has implemented a comprehensive program for rare diseases (RD) that includes an epidemiological program as well as the establishment of expert centers for the clinical care of patients with RD. Since 2007, most of these centers have entered the data for patients with developmental disorders into the CE...
Article
Transcription factor IID is a multimeric protein complex that is essential for the initiation of transcription by RNA polymerase II. One of its critical components, the TATA-binding protein-associated factor 2, is encoded by the gene TAF2. Pathogenic variants of this gene have been shown to be responsible for the Mental retardation, autosomal reces...
Preprint
Full-text available
Numerous countries have set up population genomics plans, allowing an unprecedented growth in the ability of interpreting variants in human diseases. Retrospective interpretation of sequenced data in the light of the current literature is a major concern of the field. Moreover, such reinterpretation is manual and both the human resources and the va...
Article
Full-text available
Background 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 Mendel...
Preprint
Full-text available
ABBSTRACT DYRK1A -related intellectual disability (ID) is among the most frequent monogenic form of ID. We refined the description of this disorder by reporting clinical and molecular data of forty individuals with ID harboring DYRK1A variants. We developed a combination of tools to interpret missense variants, which remains a major challenge in hu...
Article
KBG Syndrome is a rare syndrome characterized by facial and hand anomalies, postnatal short stature, delayed bone age, intellectual disability and macrodontia. A key role of mutations in ANRKD11 gene was observed not only in central nervous system but also in skeletal development and function. Indeed, a meticulous evaluation of bone metabolism was...
Article
Herein, we report the screening of a large panel of genes in a series of 80 fetuses with congenital heart defects (CHDs) and/or heterotaxy and no cytogenetic anomalies. There were 49 males (61%/39%), with a family history in 28 cases (35%) and no parental consanguinity in 77 cases (96%). All fetuses had complex CHD except one who had heterotaxy and...
Article
KCNN2 encodes the small conductance calcium-activated potassium channel 2 (SK2). Rodent models with spontaneous Kcnn2 mutations show abnormal gait and locomotor activity, tremor and memory deficits, but human disorders related to KCNN2 variants are largely unknown. Using exome sequencing, we identified a de novo KCNN2 frameshift deletion in a patie...
Article
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Developmental disorders (DD), characterized by malformations/dysmorphism and/or intellectual disability, affecting around 3% of worldwide population, are mostly linked to genetic anomalies. Despite clinical exome sequencing (cES) centered on genes involved in human genetic disorders, the majority of patients affected by DD remain undiagnosed after...
Article
Multicystic renal dysplasia is a congenital cystic anomaly of the kidney caused by abnormal metanephric differentiation with immature tubules. It is surrounded by mesenchymal collars and islands of immature mesenchyma present between the cysts. The PI3K-AKT-mTOR signaling pathway is a key regulator involved in cell growth, proliferation, motility,...
Article
Purpose Molecular diagnosis based on singleton exome sequencing (sES) is particularly challenging in fetuses with multiple congenital abnormalities (MCA). Indeed, some studies reveal a diagnostic yield of about 20%, far lower than in live birth individuals showing developmental abnormalities (30%), suggesting that standard analyses, based on the co...
Article
Nontruncating variants in SMARCA2, encoding a catalytic subunit of SWI/SNF chromatin remodeling complex, cause Nicolaides–Baraitser syndrome (NCBRS), a condition with intellectual disability and multiple congenital anomalies. Other disorders due to SMARCA2 are unknown. By next-generation sequencing, we identified candidate variants in SMARCA2 in 20...
Article
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Mutations in chromatin-modifying complexes and metabolic enzymes commonly underlie complex human developmental syndromes affecting multiple organs. A major challenge is to determine how disease-causing genetic lesions cause deregulation of homeostasis in unique cell types. Here we show that neural-specific depletion of three members of the non-spec...
Article
PITX1 is a homeobox transcription factor essential for hindlimb morphogenesis. Two PITX1 ‐related human disorders have been reported to date: PITX1 ectopic expression causes Liebenberg syndrome, characterized by malformation of upper limbs showing a “lower limb” appearance; PITX1 deletions or missense variation cause a syndromic picture including c...
Article
Introduction Pigmentary mosaicism (PM) manifests by pigmentation anomalies along Blaschko’s lines and represents a clue toward the molecular diagnosis of syndromic intellectual disability (ID). Together with new insights on the role for lysosomal signalling in embryonic stem cell differentiation, mutations in the X-linked transcription factor 3 ( T...
Article
Full-text available
Cells rely on a diverse repertoire of genes for maintaining homeostasis, but the transcriptional networks underlying their expression remain poorly understood. The MOF acetyltransferase-containing Non-Specific Lethal (NSL) complex is a broad transcription regulator. It is essential in Drosophila, and haploinsufficiency of the human KANSL1 subunit r...
Article
De novo germline mutations in the RNA helicase DDX3X account for 1%–3% of unexplained intellectual disability (ID) cases in females and are associated with autism, brain malformations, and epilepsy. Yet, the developmental and molecular mechanisms by which DDX3X mutations impair brain function are unknown. Here, we use human and mouse genetics and c...
Article
SOX6 belongs to a family of 20 SRY-related HMG-box-containing (SOX) genes that encode transcription factors controlling cell fate and differentiation in many developmental and adult processes. For SOX6, these processes include, but are not limited to, neurogenesis and skeletogenesis. Variants in half of the SOX genes have been shown to cause severe...
Article
Purpose Marfanoid habitus (MH) combined with intellectual disability (ID) (MHID) is a clinically and genetically heterogeneous presentation. The combination of array CGH and targeted sequencing of genes responsible for Marfan or Lujan–Fryns syndrome explain no more than 20% of subjects. Methods To further decipher the genetic basis of MHID, we per...
Article
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SKI pathogenic variations are associated with Shprintzen–Goldberg Syndrome (SGS), a rare systemic connective tissue disorder characterized by craniofacial, skeletal and cardiovascular features. So far, the clinical description, including intellectual disability, has been relatively homogeneous, and the known pathogenic variations were located in tw...
Article
X‐linked intellectual disability (XLID) is a genetically heterogeneous condition involving more than 100 genes. To date, 35 pathogenic variants have been reported in the lysine specific demethylase 5C (KDM5C) gene. KDM5C variants are one of the major causes of moderate to severe XLID. Affected males present with short stature, distinctive facial fe...
Article
Overlapping syndromes such as Noonan, Cardio‐Facio‐Cutaneous, Noonan syndrome with multiple lentigines and Costello syndromes are genetically heterogeneous conditions sharing a dysregulation of the RAS/MAPK pathway and are known collectively as the RASopathies. PTPN11 was the first disease‐causing gene identified in Noonan syndrome and remains the...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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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...
Article
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Background: Structural variants (SVs) include copy number variants (CNVs) and apparently balanced chromosomal rearrangements (ABCRs). Genome sequencing (GS) enables SV detection at base-pair resolution, but the use of short-read sequencing is limited by repetitive sequences, and long-read approaches are not yet validated for diagnosis. Recently, 1...
Article
In 2011, KIAA1033/WASHC4 was associated with autosomal recessive intellectual disability (ARID) in a large consanguineous family comprising seven affected individuals with moderate ID and short stature. Since then, no other cases of KIAA1033 variants have been reported. Here we describe three additional patients (from two unrelated families) with s...
Article
Full-text available
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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Hypopigmentation along Blaschko’s lines is a hallmark of a poorly defined group of mosaic syndromes whose genetic causes are unknown. Here we show that postzygotic inactivating mutations of RHOA cause a neuroectodermal syndrome combining linear hypopigmentation, alopecia, apparently asymptomatic leukoencephalopathy, and facial, ocular, dental and a...
Article
Full-text available
Early infantile epileptic encephalopathy (EIEE) is a heterogeneous group of severe forms of age-related developmental and epileptic encephalopathies with onset during the first weeks or months of life. The interictal electroencephalogram (EEG) shows a “suppression burst” (SB) pattern. The prognosis is usually poor and most children die within the f...
Article
The RNA polymerase II complex (pol II) is responsible for transcription of all ∼21,000 human protein-encoding genes. Here, we describe sixteen individuals harboring de novo heterozygous variants in POLR2A, encoding RPB1, the largest subunit of pol II. An iterative approach combining structural evaluation and mass spectrometry analyses, the use of S...
Article
Alpha‐mannosidosis (AM) is a very rare (prevalence: 1/500000 births) autosomal recessive lysosomal storage disorder. It is characterized by multi‐systemic involvement associated with progressive intellectual disability, hearing loss, skeletal anomalies, and coarse facial features. The spectrum is wide, from very severe and lethal to a milder phenot...
Article
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In clinical exome sequencing (cES), the American College of Medical Genetics and Genomics recommends limiting variant interpretation to established human-disease genes. The diagnostic yield of cES in intellectual disability and/or multiple congenital anomalies (ID/MCA) is currently about 30%. Though the results may seem acceptable for rare diseases...
Article
KCNMA1 encodes the BK potassium channel α-subunit and pathogenic gain-of-function variants in this gene have been associated with a dominant form of generalized epilepsy and paroxysmal dyskinesia. Here, we genetically and functionally characterize 8 novel loss-of-function (LoF) variants of KCNMA1. Genome or exome sequencing and the participation in...
Article
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The HTML and PDF versions of this Article were updated after publication to remove images of one individual from Figure 1.
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Cohen syndrome (CS) is a rare genetic disorder due to mutations in VPS13B gene. Among various clinical and biological features, CS patients suffer from inconsistent neutropenia, which is associated with recurrent but minor infections. We demonstrate here that this neutropenia results from an exaggerate rate of neutrophil apoptosis. Besides this inc...
Article
With exome/genome sequencing (ES/GS) integrated into the practice of medicine, there is some potential for reporting incidental/secondary findings (IFs/SFs). The issue of IFs/SFs has been studied extensively over the last 4 years. In order to evaluate their implications in care organisation, we retrospectively evaluated, in a cohort of 700 consecut...
Article
这份来自德国和法国的报告描述了 4 名局灶性真皮发育不全 (FDH) 女性,FDH 是一种影响皮肤、骨骼、牙齿和眼睛的遗传病。FDH 因位于 X 染色体的称为 PORCN 的突变(异常)基因导致。存在此突变基因的男性胚胎通常不能存活。女性更为复杂。首先,她们有两条 X 染色体,但对于发生 FDH,它只需要一条染色体上存在突变基因。其次,在妊娠后,所有胚胎细胞中两条染色体中的一条被随机失活。来自正常X 染色体的细胞系(姊妹细胞)处于正常的活化发育过程;而来自异常 X 染色体的细胞系由于该突变基因处于异常活化发育过程。这种现象被称为嵌合现象(并顺便解释了玳瑁猫为何总为雌性),在此现象中,个体的细胞系代表了不同的遗传群体。FDH 突变还常在授精后于发育的初期自发发生,但在 X 染色体失活之前。来自...
Article
This report from Germany and France describes four women with focal dermal hypoplasia (FDH), a genetic condition affecting the skin, skeleton, teeth and eyes. FDH is caused by a mutant (abnormal) gene called PORCN, found on the X chromosome. Male embryos with the mutant gene do not usually survive. Females are more complicated. Firstly, they have t...
Article
By using exome sequencing and a gene matching approach, we identified de novo and inherited pathogenic variants in KDM3B in 14 unrelated individuals and three affected parents with varying degrees of intellectual disability (ID) or developmental delay (DD) and short stature. The individuals share additional phenotypic features that include feeding...
Article
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The original version of this Article contained an error in the spelling of the author Laurence Faivre, which was incorrectly given as Laurence Faive. This has now been corrected in both the PDF and HTML versions of the Article.
Article
The AMME syndrome defined as the combination of Alport syndrome, intellectual disability, midface hypoplasia, and elliptocytosis (AMME) is known to be a contiguous gene syndrome associated with microdeletions in the region Xq22.3q23. Recently, using exome sequencing, missense pathogenic variants in AMMECR1 have been associated with intellectual dis...
Article
Exome sequencing (ES) has revolutionized diagnostic procedures in medical genetics, particularly for developmental diseases. The variety and complexity of the information produced has raised issues regarding its use in a clinical setting. Of particular interest are patients’ expectations regarding the information disclosed, the accompaniment provid...
Conference Paper
51st Conference of the European-Society-of-Human-Genetics (ESHG) in conjunction with the European Meeting on Psychosocial Aspects of Genetics (EMPAG), Milan, ITALY, JUN 16-19, 2018
Article
Purpose Lanosterol synthase (LSS) gene was initially described in families with extensive congenital cataracts. Recently, a study has highlighted LSS associated with hypotrichosis simplex. We expanded the phenotypic spectrum of LSS to a recessive neuroectodermal syndrome formerly named alopecia with mental retardation (APMR) syndrome. It is a rare...
Article
Purpose: Exome sequencing (ES) powerfully identifies the molecular bases of heterogeneous conditions such as intellectual disability and/or multiple congenital anomalies (ID/MCA). Current ES analysis, combining diagnosis analysis restricted to disease-causing genes reported in OMIM database and subsequent research investigation extended to other g...
Article
The oculoauriculofrontonasal syndrome (OAFNS) is a rare disorder characterized by the association of frontonasal dysplasia (widely spaced eyes, facial cleft, and nose abnormalities) and oculo‐auriculo‐vertebral spectrum (OAVS)‐associated features, such as preauricular ear tags, ear dysplasia, mandibular asymmetry, epibulbar dermoids, eyelid colobom...
Article
Full-text available
SMARCC2 (BAF170) is one of the invariable core subunits of the ATP-dependent chromatin remodeling BAF (BRG1-associated factor) complex and plays a crucial role in embryogenesis and corticogenesis. Pathogenic variants in genes encoding other components of the BAF complex have been associated with intellectual disability syndromes. Despite its signif...