Publications by authors named "Pierre-Simon Jouk"

67 Publications

Phenotypic spectrum and genomics of undiagnosed arthrogryposis multiplex congenita.

J Med Genet 2021 Apr 5. Epub 2021 Apr 5.

Department of Pediatric Neurology, APHP-Bicêtre Hospital, Le Kremlin-Bicêtre, France.

Background: Arthrogryposis multiplex congenita (AMC) is characterised by congenital joint contractures in two or more body areas. AMC exhibits wide phenotypic and genetic heterogeneity. Our goals were to improve the genetic diagnosis rates of AMC, to evaluate the added value of whole exome sequencing (WES) compared with targeted exome sequencing (TES) and to identify new genes in 315 unrelated undiagnosed AMC families.

Methods: Several genomic approaches were used including genetic mapping of disease loci in multiplex or consanguineous families, TES then WES. Sanger sequencing was performed to identify or validate variants.

Results: We achieved disease gene identification in 52.7% of AMC index patients including nine recently identified genes (, , , , , , , and ). Moreover, we identified pathogenic variants in and expanding the phenotypes associated with these genes. The most frequent cause of AMC was a primary involvement of skeletal muscle (40%) followed by brain (22%). The most frequent mode of inheritance is autosomal recessive (66.3% of patients). In sporadic patients born to non-consanguineous parents (n=60), de novo dominant autosomal or X linked variants were observed in 30 of them (50%).

Conclusion: New genes recently identified in AMC represent 21% of causing genes in our cohort. A high proportion of de novo variants were observed indicating that this mechanism plays a prominent part in this developmental disease. Our data showed the added value of WES when compared with TES due to the larger clinical spectrum of some disease genes than initially described and the identification of novel genes.
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http://dx.doi.org/10.1136/jmedgenet-2020-107595DOI Listing
April 2021

Next-generation sequencing in a series of 80 fetuses with complex cardiac malformations and/or heterotaxy.

Hum Mutat 2020 Dec 10;41(12):2167-2178. Epub 2020 Nov 10.

Centre de Génétique Humaine, CHU Franche-Comté, Besançon, France.

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 midline anomalies while 52 cases (65%) had heterotaxy in addition to CHD. Altogether, 29 cases (36%) had extracardiac and extra-heterotaxy anomalies. A pathogenic variant was found in 10/80 (12.5%) cases with a higher percentage in the heterotaxy group (8/52 cases, 15%) compared with the non-heterotaxy group (2/28 cases, 7%), and in 3 cases with extracardiac and extra-heterotaxy anomalies (3/29, 10%). The inheritance was recessive in six genes (DNAI1, GDF1, MMP21, MYH6, NEK8, and ZIC3) and dominant in two genes (SHH and TAB2). A homozygous pathogenic variant was found in three cases including only one case with known consanguinity. In conclusion, after removing fetuses with cytogenetic anomalies, next-generation sequencing discovered a causal variant in 12.5% of fetal cases with CHD and/or heterotaxy. Genetic counseling for future pregnancies was greatly improved. Surprisingly, unexpected consanguinity accounts for 20% of cases with identified pathogenic variants.
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http://dx.doi.org/10.1002/humu.24132DOI Listing
December 2020

Polarized Light Imaging of the Myoarchitecture in Tetralogy of Fallot in the Perinatal Period.

Front Pediatr 2020 22;8:503054. Epub 2020 Sep 22.

Centre National de la Recherche Scientifique (CNRS), Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques, Applications, Grenoble (TIMC-IMAG), Grenoble, France.

The pathognomonic feature of tetralogy of Fallot (ToF) is the antero-cephalad deviation of the outlet septum in combination with an abnormal arrangement of the septoparietal trabeculations. The aim of this article was to study perinatal hearts using Polarized Light Imaging (PLI) in order to investigate the deep alignment of cardiomyocytes that bond the different components of the ventricular outflow tracts both together and to the rest of the ventricular mass, thus furthering the classic description of ToF. 10 perinatal hearts with ToF and 10 perinatal hearts with no detectable cardiac anomalies (control) were studied using PLI. The orientation of the myocardial cells was extracted and studied at high resolution. Virtual dissections in multiple section planes were used to explore each ventricular structure. Contrary to the specimens of the control group, for all ToF specimens studied, the deep latitudinal alignment of the cardiomyocytes bonds together the left part of the Outlet septum (OS) S to the anterior wall of the left ventricle. In addition, the right end of the muscular OS bonds directly on the right ventricular wall (RVW) superior to the attachment of the ventriculo infundibular fold (VIF). Thus, the OS is a bridge between the lateral RVW and the anterior left ventricular wall. The VIF, RVW, and OS define an "inverted U" that roofs the cone between the interventricular communication and the overriding aorta. The opening angle and the length of the branches of this "inverted U" depend however on three components: the size of the OS, the size of the VIF, and the distance between the points of insertion of the OS and VIF into the RVW. The variation of these three components accounts for a significant part of the diversity observed in the anatomical presentations of ToF in the perinatal period.
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http://dx.doi.org/10.3389/fped.2020.503054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7536283PMC
September 2020

High Activation of the AKT Pathway in Human Multicystic Renal Dysplasia.

Pathobiology 2020 14;87(5):302-310. Epub 2020 Sep 14.

Department of Pathology, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble, France,

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, survival, and apoptosis. Activation of the PI3K-AKT-mTOR pathway results in the survival and proliferation of tumor cells in many cancers. The aim of this study is to analyze the topographic expression of phospho-AKT, phospho-mTOR, and phospho-70S6K in renal development and in the multicystic dysplastic kidney (MCDK). A total of 17 fetal kidneys of development age from the first to the third trimester and 13 cases of pathological kidneys with MCDK were analyzed by immunohistochemistry in order to evaluate the expression of phospho-AKT (S473), phospho-mTOR, and phospho-70S6K. Phospho-AKT and phospho-mTOR were expressed early in renal development and in an identical manner for every structure derived from the ureteric bud, such as collecting ducts and urothelium. Phospho-p70S6K was expressed early in the urothelium and in glomerular mesangial cells. Later, their expressions differed according to the needs of cell proliferation and differentiation over time by becoming more selective. In MCDK, phospho-AKT, phospho-mTOR, and phospho-70S6K have the same profile: a high cytoplasmic expression in cystic epithelium, loose mesenchyma, and primitive tubes. This study demonstrates the essential and specific role of the PI3K-AKT-mTOR pathway in the formation of cysts in multicystic renal dysplasia.
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http://dx.doi.org/10.1159/000509152DOI Listing
September 2020

Excess of de novo variants in genes involved in chromatin remodelling in patients with marfanoid habitus and intellectual disability.

J Med Genet 2020 07 10;57(7):466-474. Epub 2020 Apr 10.

Centre de Compétence Anomalies du Développement et Syndromes Malformatifs Sud-Est, CHI de Toulon - La Seyne-sur-Mer, France.

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 performed exome sequencing on a combination of trio-based (33 subjects) or single probands (31 subjects), of which 61 were sporadic.

Results: We identified eight genes with de novo variants (DNVs) in at least two unrelated individuals ( and ). Using simulation models, we showed that five genes ( and ) met conservative Bonferroni genomewide significance for an excess of the observed de novo point variants. Overall, at least one pathogenic or likely pathogenic variant was identified in 54.7% of subjects (35/64). These variants fell within 27 genes previously associated with Mendelian disorders, including and , which are known to be mutated in overgrowth syndromes.

Conclusion: We demonstrated that DNVs were enriched in chromatin remodelling (p=2×10) and genes regulated by the fragile X mental retardation protein (p=3×10), highlighting overlapping genetic mechanisms between MHID and related neurodevelopmental disorders.
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http://dx.doi.org/10.1136/jmedgenet-2019-106425DOI Listing
July 2020

TAR syndrome: Clinical and molecular characterization of a cohort of 26 patients and description of novel noncoding variants of RBM8A.

Hum Mutat 2020 07 6;41(7):1220-1225. Epub 2020 Apr 6.

Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France.

Thrombocytopenia-absent radius (TAR) syndrome is characterized by radial defect and neonatal thrombocytopenia. It is caused by biallelic variants of RBM8A gene (1q21.1) with the association of a null allele and a hypomorphic noncoding variant. RBM8A encodes Y14, a core protein of the exon junction complex involved in messenger RNA maturation. To date, only two hypomorphic variants have been identified. We report on a cohort of 26 patients affected with TAR syndrome and carrying biallelic variants in RBM8A. Half patients carried a 1q21.1 deletion and one of the two known hypomorphic variants. Four novel noncoding variants of RBM8A were identified in the remaining patients. We developed experimental models enabling their functional characterization in vitro. Two variants, located respectively in the 5'-untranslated region (5'-UTR) and 3'-UTR regions, are responsible for a diminished expression whereas two intronic variants alter splicing. Our results bring new insights into the molecular knowledge of TAR syndrome and enabled us to propose genetic counseling for patients' families.
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http://dx.doi.org/10.1002/humu.24021DOI Listing
July 2020

Prenatal Diagnosis of Aorto-Left Ventricular Tunnel With Dysplastic Bicuspid Aortic Valve: From Fetal Cardiac Failure to Favorable Outcome.

Front Pediatr 2020 27;8:69. Epub 2020 Feb 27.

Pediatric Cardiac Unit, Hôpital Universitaire de Grenoble-Alpes, Grenoble, France.

Aorto-left ventricular tunnel (ALVT) is a rare congenital heart defect. Surgery has to be performed early to avoid life-threatening complications. Prenatal diagnosis of this defect is challenging. We report a case of ALVT diagnosed in a fetus showing premature severe cardiac failure at 24 GA. The new born was operated at day 3 of life with good results. Two years later, he is still doing well recovering a complete normal cardiac function. ALVT should be suggested in front of any fetal cardiac failure. Thanks to early diagnosis, prompt neonatal management can be organized and allows positive outcome.
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http://dx.doi.org/10.3389/fped.2020.00069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7056665PMC
February 2020

Longitudinal Study by Two-Dimensional Speckle-Tracking Echocardiography of the Left Ventricle Rotational Mechanics during Postnatal Adaptation in Healthy Newborns.

J Am Soc Echocardiogr 2020 02 4;33(2):252-254. Epub 2019 Dec 4.

DyCTim Team, TIMC-IMAG Laboratory, La Tronche, France; Department of Genetics, Grenoble Alpes University Hospital, Grenoble, France.

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http://dx.doi.org/10.1016/j.echo.2019.09.017DOI Listing
February 2020

The diagnostic workup in a patient with AMC: Overview of the clinical evaluation and paraclinical analyses with review of the literature.

Am J Med Genet C Semin Med Genet 2019 09 1;181(3):337-344. Epub 2019 Aug 1.

Robert Wood Johnson School of Medicine, Rutgers University, New Brunswick, New Jersey, USA.

Arthrogryposis multiplex congenita, or AMC, is a clinical sign defined as congenital contractures of at least two joint levels. These joint contractures are always secondary to diminished fetal movement which can have numerous causes that affect any part of the anatomical structures implicated in movement: the central nervous system, the anterior horn cell, the nerve, the neuromuscular junction, the muscle, or the joint itself. Make a precise diagnosis of the cause in a patient with multiple joint contractures is therefore challenging. The aim of this article is to summarize the use and diagnostic value of common examinations and analyses performed postnatally in patients affected by AMC from a literature review. We also compare this data with results from our clinical practice. Even though it is difficult to give precise guidelines today, it appears that genetic studies, such as whole exome or genome analysis in all patients and chromosomal microarray analysis in patients with intellectual disability and AMC should be preferred as first tier investigations over EMG and muscle biopsy.
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http://dx.doi.org/10.1002/ajmg.c.31730DOI Listing
September 2019

Xq22.3q23 microdeletion harboring TMEM164 and AMMECR1 genes: Two case reports confirming a recognizable phenotype with short stature, midface hypoplasia, intellectual delay, and elliptocytosis.

Am J Med Genet A 2019 04 8;179(4):650-654. Epub 2019 Feb 8.

Département de Génétique et Procréation, Centre Hospitalo-Universitaire Grenoble Alpes, Grenoble Cedex, France.

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 disability, midface hypoplasia, and elliptocytosis. In these cases, AMMECR1 gene appears to be responsible for most of the clinical features of the AMME syndrome except for Alport syndrome. In this article, we present two unrelated male patients with short stature, mild intellectual disability or neurodevelopmental delay, sensorineural hearing loss, and elliptocytosis harboring small microdeletions identified by array-CGH involving TMEM164 and AMMECR1 genes and SNORD96B small nucleolar RNA for one patient, inherited from their mothers. These original cases further confirm that most specific AMME features are ascribed to AMMECR1 haploinsufficiency. These cases reporting the smallest microdeletions encompassing AMMECR1 gene provide new evidence for involvement of AMMECR1 in the AMME phenotype and permit to discuss a phenotype related to AMMECR1 haploinsufficiency: developmental delay/intellectual deficiency, midface hypoplasia, midline defect, deafness, and short stature.
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http://dx.doi.org/10.1002/ajmg.a.61057DOI Listing
April 2019

Dysregulations of sonic hedgehog signaling in MED12-related X-linked intellectual disability disorders.

Mol Genet Genomic Med 2019 04 6;7(4):e00569. Epub 2019 Feb 6.

Institute of Genetic Medicine and Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland.

Background: Mutations in mediator of RNA polymerase II transcription subunit 12 homolog (MED12, OMIM 300188) cause X-linked intellectual disability (XLID) disorders including FG, Lujan, and Ohdo syndromes. The Gli3-dependent Sonic Hedgehog (SHH) signaling pathway has been implicated in the original FG syndrome and Lujan syndrome. How are SHH-signaling defects related to the complex clinical phenotype of MED12-associated XLID syndromes are not fully understood.

Methods: Quantitative RT-PCR was used to study expression levels of three SHH-signaling genes in lymophoblast cell lines carrying four MED12 mutations from four unrelated XLID families. Genotype and phenotype correlation studies were performed on these mutations.

Results: Three newly identified and one novel MED12 mutations in six affected males from four unrelated XLID families were studied. Three mutations (c.2692A>G; p.N898D, c.3640C>T; p.R1214C, and c.3884G>A; p.R1295H) are located in the LS domain and one (c.617G>A; p.R206Q) is in the L domain of MED12. These mutations involve highly conserved amino acid residues and segregate with ID and related congenital malformations in respective probands families. Patients with the LS-domain mutations share many features of FG syndrome and some features of Lujan syndrome. The patient with the L-domain mutation presented with ID and predominant neuropsychiatric features but little dysmorphic features of either FG or Lujan syndrome. Transcript levels of three Gli3-dependent SHH-signaling genes, CREB5, BMP4, and NEUROG2, were determined by quantitative RT-PCR and found to be significantly elevated in lymphoblasts from patients with three mutations in the MED12-LS domain.

Conclusions: These results support a critical role of MED12 in regulating Gli3-dependent SHH signaling and in developing ID and related congenital malformations in XLID syndromes. Differences in the expression profile of SHH-signaling genes potentially contribute to variability in clinical phenotypes in patients with MED12-related XLID disorders.
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http://dx.doi.org/10.1002/mgg3.569DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465656PMC
April 2019

Quantitative comparison of human myocardial fiber orientations derived from DTI and polarized light imaging.

Phys Med Biol 2018 10 23;63(21):215003. Epub 2018 Oct 23.

School of Computer and Information Technology, Beijing Jiaotong University, Beijing, People's Republic of China. Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69621, LYON, France. Author to whom any correspondence should be addressed.

Diffusion tensor imaging (DTI) is a non-invasive technique used to obtain the 3D fiber structure of whole human hearts, for both in vivo and ex vivo cases. However, by essence, DTI does not measure directly the orientations of myocardial fibers. In contrast, polarized light imaging (PLI) allows for physical measurements of fiber orientations, but only for ex vivo case. This work aims at quantitatively comparing the myocardial fiber orientations of whole human hearts obtained from cardiac DTI with those measured by PLI. Whole human neonatal and infant hearts were first imaged using DTI. The same whole hearts were then imaged using PLI. After DTI and PLI data are registered, the orientations of fibers from the two imaging modalities were finally quantitatively compared. The results show that DTI and PLI have similar variation patterns of elevation and azimuth angles, with some differences in transmural elevation angle range. DTI itself induces an underestimation of the range of transmural elevation angles by a factor of about 25° at the basal and equatorial slices and the reduction of spatial resolution further decreases this range. PLI data exhibit a 15°  ±  5° (P  <  0.01) narrower transmural elevation angle range at apical slices than in basal or equatorial slices. This phenomenon is not observed in DTI data. In both modalities, the azimuth angle maps exhibit curved or twisting boundaries at the basal and apical slices. The experimental results globally enforce DTI as a valid imaging technique to reasonably characterize fiber orientations of the human heart noninvasively.
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http://dx.doi.org/10.1088/1361-6560/aae514DOI Listing
October 2018

Genomic duplication in the 19q13.42 imprinted region identified as a new genetic cause of intrauterine growth restriction.

Clin Genet 2018 12 17;94(6):575-580. Epub 2018 Oct 17.

INSERM U1205, UFR Chimie Biologie, Grenoble, France.

We report findings from a male fetus of 26 weeks' gestational age with severe isolated intrauterine growth restriction (IUGR). Chromosomal microarray analysis (CMA) on amniotic fluid cells revealed a 1.06-Mb duplication in 19q13.42 inherited from the healthy father. This duplication contains 34 genes including ZNF331, a gene encoding a zinc-finger protein specifically imprinted (paternally expressed) in the placenta. Study of the ZNF331 promoter by methylation-specific-multiplex ligation-dependent probe amplification showed that the duplicated allele was not methylated in the fetus unlike in the father's genome, suggesting both copies of the ZNF331 gene are expressed in the fetus. The anti-ZNF331 immunohistochemical analysis confirmed that ZNF331 was expressed at higher levels in renal and placental tissues from this fetus compared to controls. Interestingly, ZNF331 expression levels in the placenta have previously been reported to inversely correlate with fetal growth parameters. The original observation presented in this report showed that duplication of ZNF331 could be a novel genetic cause of isolated IUGR and underlines the usefulness of CMA to investigate the genetic causes of isolated severe IUGR.
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http://dx.doi.org/10.1111/cge.13449DOI Listing
December 2018

Major intra-familial phenotypic heterogeneity and incomplete penetrance due to a CACNA1A pathogenic variant.

Eur J Med Genet 2019 Jun 22;62(6):103530. Epub 2018 Aug 22.

Service de Génétique Médicale, CHU de Bordeaux and Laboratoire MRGM, INSERM U1211, Univ. Bordeaux, Bordeaux, France; Centre de Référence Neurogénétique, Service de Génétique Médicale, CHU de Bordeaux, France.

The CACNA1A gene encodes a calcium-dependent voltage channel, localized in neuronal cells. Pathogenic variants in this gene are known to lead to a broad clinical spectrum including episodic ataxia type 2, spinocerebellar ataxia type 6, familial hemiplegic migraine, and more recently epileptic encephalopathy. We report a large family revealing a wide variability of neurological manifestations associated with a CACNA1A missense pathogenic variant. The index case had early-onset epileptic encephalopathy with progressive cerebellar atrophy, although his mother and his great-grandmother suffered from paroxystic episodic ataxia. His grandfather and great grand-aunt reported no symptoms, but two of her sons displayed early-onset ataxia with intellectual disability. Two of her little daughters suffered from gait disorders, and also from epilepsy for one of them. All these relatives were carriers of the previously described heterozygous variant in CACNA1A gene. We report here the first family leading to major clinical variability and incomplete penetrance. Our family highlights the difficulties to provide accurate genetic counselling concerning prenatal diagnosis regarding highly variable severity of the clinical presentation.
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http://dx.doi.org/10.1016/j.ejmg.2018.08.011DOI Listing
June 2019

Disability in adults with arthrogryposis is severe, partly invisible, and varies by genotype.

Neurology 2018 05 6;90(18):e1596-e1604. Epub 2018 Apr 6.

From the Service de Rééducation Neurologique, Institut de Rééducation Hôpital Sud (S.D., M.J., D.P.), and Département Thoracique et Vasculaire, Laboratoire Sommeil & Exercice (B.W.), Hôpital Universitaire Grenoble-Alpes; Laboratoire de Psychologie et Neurocognition (LPNC), CNRS (S.D., D.P.), INSERM, Grenoble Institut des Neurosciences (GIN) (K.D., D.P.), INSERM, HP2 Laboratory (B.W.), and TIMC-IMAG, CNRS (P.-S.J.), Universitaire Grenoble Alpes; and Service de Génétique Clinique (K.D., P.-S.J.), Hôpital Couple Enfant, CHU Grenoble Alpes, Grenoble, France.

Objective: To understand the disability of adults with arthrogryposis multiplex congenita (AMC), a rare disease spectrum characterized by at least 2 joint contractures at birth in different body areas.

Methods: This is a retrospective analysis of data for unselected persons with AMC referred to the French center for adults with AMC from 2010 to 2016. All underwent a pluriprofessional systematic and comprehensive investigation of deficits, activity limitation, and participation restriction according to the International Classification of Functioning, Disability and Health and genetic analysis when indicated. Participants were divided by amyoplasia and other AMC types.

Results: Mean (SD) age of the 43 participants (27 female) was 33.2 (13.4) years; 28 had amyoplasia and 15 other types of AMC. Beyond joint stiffness, deformities, and muscle weakness, the well-known core symptoms that we quantified and for which first-line treatment involved technical aids, other less visible disorders that could contribute to severe participation restriction were particularly pain and psychological problems including anxiety, fatigue, difficulty in sexual life, altered self-esteem, and feelings of solitude. Severe respiratory disorders were infrequent and were linked to mutations. Gait disorders were not due to respiratory impairment but to skeletal problems and were always associated with amyoplasia when severe. Functional independence was worse but respiratory and swallowing capacities were better with amyoplasia than other AMC types.

Conclusion: This study describes disability patterns of a cohort of adults with AMC by genotype. The disability of adults with AMC is influenced by genotype, with important invisible disability.
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http://dx.doi.org/10.1212/WNL.0000000000005418DOI Listing
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

Mutations in CFAP43 and CFAP44 cause male infertility and flagellum defects in Trypanosoma and human.

Nat Commun 2018 02 15;9(1):686. Epub 2018 Feb 15.

Institut National de la Santé et de la Recherche Médicale, INSERM U1016, Institut Cochin, 75014, Paris, France.

Spermatogenesis defects concern millions of men worldwide, yet the vast majority remains undiagnosed. Here we report men with primary infertility due to multiple morphological abnormalities of the sperm flagella with severe disorganization of the sperm axoneme, a microtubule-based structure highly conserved throughout evolution. Whole-exome sequencing was performed on 78 patients allowing the identification of 22 men with bi-allelic mutations in DNAH1 (n = 6), CFAP43 (n = 10), and CFAP44 (n = 6). CRISPR/Cas9 created homozygous CFAP43/44 male mice that were infertile and presented severe flagellar defects confirming the human genetic results. Immunoelectron and stimulated-emission-depletion microscopy performed on CFAP43 and CFAP44 orthologs in Trypanosoma brucei evidenced that both proteins are located between the doublet microtubules 5 and 6 and the paraflagellar rod. Overall, we demonstrate that CFAP43 and CFAP44 have a similar structure with a unique axonemal localization and are necessary to produce functional flagella in species ranging from Trypanosoma to human.
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http://dx.doi.org/10.1038/s41467-017-02792-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5814398PMC
February 2018

CHARGE syndrome: a recurrent hotspot of mutations in CHD7 IVS25 analyzed by bioinformatic tools and minigene assays.

Eur J Hum Genet 2018 02 18;26(2):287-292. Epub 2017 Dec 18.

Service de Génétique, Centre de Référence Anomalies du Développement de l'Ouest, CHU Poitiers, France.

CHARGE syndrome is a rare genetic disorder mainly due to de novo and private truncating mutations of CHD7 gene. Here we report an intriguing hot spot of intronic mutations (c.5405-7G > A, c.5405-13G > A, c.5405-17G > A and c.5405-18C > A) located in CHD7 IVS25. Combining computational in silico analysis, experimental branch-point determination and in vitro minigene assays, our study explains this mutation hot spot by a particular genomic context, including the weakness of the IVS25 natural acceptor-site and an unconventional lariat sequence localized outside the common 40 bp upstream the acceptor splice site. For each of the mutations reported here, bioinformatic tools indicated a newly created 3' splice site, of which the existence was confirmed using pSpliceExpress, an easy-to-use and reliable splicing reporter tool. Our study emphasizes the idea that combining these two complementary approaches could increase the efficiency of routine molecular diagnosis.
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http://dx.doi.org/10.1038/s41431-017-0007-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839049PMC
February 2018

Postnatal myocardium remodelling generates inhomogeneity in the architecture of the ventricular mass.

Surg Radiol Anat 2018 Jan 28;40(1):75-83. Epub 2017 Nov 28.

Equipe DyCTim, Laboratoire TIMC-IMAG, 38706, La Tronche cedex, France.

Background: The 3D architecture of the ventricular mass is poorly known, although in vivo imaging techniques show the physiological inhomogeneity of ventricular walls mechanics. Polarized light imaging makes it possible to quantitatively analyse the myosin filament orientation.

Aims: In this paper, we focus on the study the 3D architecture and regional isotropy of myocardial cells.

Methods: Twenty normal human hearts, 10 from the perinatal period and 10 from the post-neonatal period were studied by polarized light microscopy. In each voxel of the ventricular mass (90 × 90 × 500 µm) the principal orientation segment was automatically and unambiguously extracted as well as a regional isotropy index (regional orientation tensor of the voxel neighbourhood).

Results: During the first months of postnatal age, the median regional isotropy values decreased in the ventricular mesh. This global decrease was not homogeneous across the ventricular walls. From the perinatal to the neonatal period, this decrease was more marked in the inner two-third of the lateral left ventricular wall and in the right part of the interventricular septum. There was a progressive post-neonatal appearance of a particularly inhomogeneous secondary arrangement of myocardial cells with alternation of thick low-RI and thin high-RI areas.

Conclusions: This study has shown a postnatal change in ventricular myocardial architecture, which became more inhomogeneous. The cell rearrangements responsible for the inhomogeneity in ventricular myocardial architecture are revealed by a variation of the regional isotropy index. These major changes are probably an adaptive consequence of the major haemodynamic changes occurring after birth during the neonatal period that generates major parietal stress variations and parietal remodelling.
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http://dx.doi.org/10.1007/s00276-017-1945-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5820407PMC
January 2018

Phenotype and genotype analysis of a French cohort of 119 patients with CHARGE syndrome.

Am J Med Genet C Semin Med Genet 2017 12 27;175(4):417-430. Epub 2017 Nov 27.

Service de Génétique, CHU de Lyon, Bron, France.

CHARGE syndrome (CS) is a genetic disorder whose first description included Coloboma, Heart disease, Atresia of choanae, Retarded growth and development, Genital hypoplasia, and Ear anomalies and deafness, most often caused by a genetic mutation in the CHD7 gene. Two features were then added: semicircular canal anomalies and arhinencephaly/olfactory bulb agenesis, with classification of typical, partial, or atypical forms on the basis of major and minor clinical criteria. The detection rate of a pathogenic variant in the CHD7 gene varies from 67% to 90%. To try to have an overview of this heterogenous clinical condition and specify a genotype-phenotype relation, we conducted a national study of phenotype and genotype in 119 patients with CS. Selected clinical diagnostic criteria were from Verloes (2005), updated by Blake & Prasad (). Besides obtaining a detailed clinical description, when possible, patients underwent a full ophthalmologic examination, audiometry, temporal bone CT scan, gonadotropin analysis, and olfactory-bulb MRI. All patients underwent CHD7 sequencing and MLPA analysis. We found a pathogenic CHD7 variant in 83% of typical CS cases and 58% of atypical cases. Pathogenic variants in the CHD7 gene were classified by the expected impact on the protein. In all, 90% of patients had a typical form of CS and 10% an atypical form. The most frequent features were deafness/semicircular canal hypoplasia (94%), pituitary defect/hypogonadism (89%), external ear anomalies (87%), square-shaped face (81%), and arhinencephaly/anosmia (80%). Coloboma (73%), heart defects (65%), and choanal atresia (43%) were less frequent.
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http://dx.doi.org/10.1002/ajmg.c.31591DOI Listing
December 2017

Biallelic mutation of UNC50, encoding a protein involved in AChR trafficking, is responsible for arthrogryposis.

Hum Mol Genet 2017 10;26(20):3989-3994

Institut National de la Santé et de la Recherche Médicale (Inserm) UMR-1169, Université Paris Sud, 94276 Le Kremlin Bicêtre, France.

Arthrogryposis multiplex congenita (AMC) is a developmental condition characterized by multiple joint contractures resulting from reduced or absent fetal movements. Homozygosity mapping of disease loci combined with whole exome sequencing in a consanguineous family presenting with lethal AMC allowed the identification of a homozygous frameshift deletion in UNC50 gene (c.750_751del:p.Cys251Phefs*4) in the index case. To assess the effect of the mutation, an equivalent mutation in the Caenorhabditis elegans orthologous gene was created using CRISPR/Cas9. We demonstrated that unc-50(kr331) modification caused the loss of acetylcholine receptor (AChR) expression in C. elegans muscle. unc-50(kr331) animals were as resistant to the cholinergic agonist levamisole as unc-50 null mutants suggesting that AChRs were no longer expressed in this animal model. This was confirmed by using a knock-in strain in which a red fluorescent protein was inserted into the AChR locus: no signal was detected in unc-50(kr331) background, suggesting that UNC-50, a protein known to be involved in AChR trafficking, was no longer functional. These data indicate that biallelic mutation in the UNC50 gene underlies AMC through a probable loss of AChR expression at the neuromuscular junction which is essential for the cholinergic transmission during human muscle development.
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http://dx.doi.org/10.1093/hmg/ddx288DOI Listing
October 2017

Clinico-molecular analysis of eleven patients with Hermansky-Pudlak type 5 syndrome, a mild form of HPS.

Pigment Cell Melanoma Res 2017 Jan 20;30(6):563-570. Epub 2017 Oct 20.

Service Génétique Médicale, CHU de Bordeaux, Bordeaux, France.

Hermansky-Pudlak syndrome (HPS), first described in 1959, is a rare form of syndromic oculocutaneous albinism associated with bleeding diathesis and in some cases pulmonary fibrosis and granulomatous colitis. All 10 HPS types are caused by defects in vesicle trafficking of lysosome-related organelles (LRO) proteins. The HPS5 protein associates with HPS3 and HPS6 to form the biogenesis of lysosome-related organelles complex-2 (BLOC-2). Here, we report the clinical and genetic data of 11 patients with HPS-5 analyzed in our laboratory. We report 11 new pathogenic variants. The 11 patients present with ocular features that are typical for albinism, with mild hypopigmentation, and with no other major complication, apart from a tendency to bleed. HPS-5 therefore appears as a mild form of HPS, which is often clinically undistinguishable from mild oculocutaneous or ocular forms of albinism. Molecular analysis is therefore required to establish the diagnosis of this mild HPS form, which has consequences in terms of prognosis and of clinical management of the patients.
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http://dx.doi.org/10.1111/pcmr.12608DOI Listing
January 2017

Clinical and molecular cytogenetic characterization of four unrelated patients carrying 2p14 microdeletions.

Am J Med Genet A 2017 Aug 9;173(8):2268-2274. Epub 2017 Jun 9.

Hospices Civils de Lyon, Service de Génétique, Centre de Référence Anomalies du Développement, Bron, France.

We report the clinical and molecular cytogenetic characterization of four unrelated patients from France and Spain, carrying 2p14 microdeletions and presenting with intellectual disability and dysmorphisms. 2p14 microdeletions are very rare. Seven patients have been reported so far harboring deletions including 2p14p15 and encompassing OTX1, whose haploinsufficiency is frequently associated with genitourinary defects. To date, only one patient has been reported carrying a more proximal 2p14 microdeletion which does not include OTX1. Here, we report three further patients carrying proximal 2p14 microdeletions not including OTX1 and one patient carrying a more distal 2p14p15 microdeletion including this gene, providing new insights into the associated phenotypic spectrum. First, our study and a review of the literature showed that 3/4 patients carrying proximal 2p14 microdeletions had sensorineural hearing loss, suggesting the presence of a previously unreported deafness-causing gene in this chromosomal region. Second, one patient developed a progressive cardiomyopathy, suggesting that a cardiac follow-up should be systematically warranted even in the absence of congenital heart disease. We speculate that ACTR2 and MEIS1 might respectively play a role in the pathogenesis of the observed deafness and cardiomyopathy. Third, we observed other previously unreported features such as glaucoma, retinopathy, and mild midline abnormalities including short corpus callosum, hypospadias and anteriorly placed anus. Finally, the patient carrying a 2p14p15 deletion including OTX1 had normal kidneys and genitalia, thus confirming that OTX1 haploinsufficiency is not invariably associated with genitourinary defects. In conclusion, our study contributes significantly to delineate the phenotypic spectrum of 2p14 microdeletions.
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http://dx.doi.org/10.1002/ajmg.a.38307DOI Listing
August 2017

MED12-related XLID disorders are dose-dependent of immediate early genes (IEGs) expression.

Hum Mol Genet 2017 06;26(11):2062-2075

Department of Functional Genomics and Cancer biology, IGBMC, CNRS/INSERM/Université de Strasbourg, 67404 Illkirch-Graffenstaden, France.

Mediator occupies a key role in protein coding genes expression in mediating the contacts between gene specific factors and the basal transcription machinery but little is known regarding the role of each Mediator subunits. Mutations in MED12 are linked with a broad spectrum of genetic disorders with X-linked intellectual disability that are difficult to range as Lujan, Opitz-Kaveggia or Ohdo syndromes. Here, we investigated several MED12 patients mutations (p.R206Q, p.N898D, p.R961W, p.N1007S, p.R1148H, p.S1165P and p.R1295H) and show that each MED12 mutations cause specific expression patterns of JUN, FOS and EGR1 immediate early genes (IEGs), reflected by the presence or absence of MED12 containing complex at their respective promoters. Moreover, the effect of MED12 mutations has cell-type specificity on IEG expression. As a consequence, the expression of late responsive genes such as the matrix metalloproteinase-3 and the RE1 silencing transcription factor implicated respectively in neural plasticity and the specific expression of neuronal genes is disturbed as documented for MED12/p.R1295H mutation. In such case, JUN and FOS failed to be properly recruited at their AP1-binding site. Our results suggest that the differences between MED12-related phenotypes are essentially the result of distinct IEGs expression patterns, the later ones depending on the accurate formation of the transcription initiation complex. This might challenge clinicians to rethink the traditional syndromes boundaries and to include genetic criterion in patients' diagnostic.
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http://dx.doi.org/10.1093/hmg/ddx099DOI Listing
June 2017

haploinsufficiency leads to syndromic congenital anomalies of the kidney and urinary tract (CAKUT) in humans.

J Med Genet 2017 07 7;54(7):502-510. Epub 2017 Mar 7.

Département de Génétique et Procréation, CHU Grenoble Alpes, Grenoble, France.

Background: Congenital anomalies of the kidney and urinary tract (CAKUT) represent a significant healthcare burden since it is the primary cause of chronic kidney in children. CNVs represent a recurrent molecular cause of CAKUT but the culprit gene remains often elusive. Our study aimed to define the gene responsible for CAKUT in patients with an 1q23.3q24.1 microdeletion.

Methods: We describe eight patients presenting with CAKUT carrying an 1q23.3q24.1 microdeletion as identified by chromosomal microarray analysis (CMA). Clinical features were collected, especially the renal and urinary tract phenotype, and extrarenal features. We characterised expression and localisation in fetal and adult kidneys using quantitative RT-PCR and immunohistochemistry.

Results: We defined a 276-kb minimal common region (MCR) that only overlaps with the gene. All eight patients presented with syndromic CAKUT. CAKUT were mostly bilateral renal hypoplasia (75%). The most frequent extrarenal symptoms were developmental delay and ear malformations. We demonstrate that is strongly expressed in fetal kidneys and brain and expression levels decreased in adult samples. In control fetal kidneys, PBX1 was localised in nuclei of medullary, interstitial and mesenchymal cells, whereas it was present in endothelial cells in adult kidneys.

Conclusions: Our results indicate that haploinsufficiency leads to syndromic CAKUT as supported by the -null mice model. Correct PBX1 dosage appears to be critical for normal nephrogenesis and seems important for brain development in humans. CMA should be recommended in cases of fetal renal anomalies to improve genetic counselling and pregnancy management.
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http://dx.doi.org/10.1136/jmedgenet-2016-104435DOI Listing
July 2017

Microduplication of the ARID1A gene causes intellectual disability with recognizable syndromic features.

Genet Med 2017 06 1;19(6):701-710. Epub 2016 Dec 1.

Université Grenoble-Alpes, Grenoble, France.

Purpose: To determine whether duplication of the ARID1A gene is responsible for a new recognizable syndrome.

Methods: We describe four patients with a 1p36.11 microduplication involving ARID1A as identified by array-comparative genomic hybridization . We performed comparative transcriptomic analysis of patient-derived fibroblasts using RNA sequencing and evaluated the impact of ARID1A duplication on the cell cycle using fluorescence-activated cell sorting. Functional relationships between differentially expressed genes were investigated with ingenuity pathway analysis (IPA).

Results: Combining the genomic data, we defined a small (122 kb), minimally critical region that overlaps the full ARID1A gene. The four patients shared a strikingly similar phenotype that included intellectual disability and microcephaly. Transcriptomic analysis revealed the deregulated expression of several genes previously linked to microcephaly and developmental disorders as well as the involvement of signaling pathways relevant to microcephaly, among which the polo-like kinase (PLK) pathway was especially notable. Cell-cycle analysis of patient-derived fibroblasts showed a significant increase in the proportion of cells in G1 phase at the expense of G2-M cells.

Conclusion: Our study reports a new microduplication syndrome involving the ARID1A gene. This work is the first step in clarifying the pathophysiological mechanism that links changes in the gene dosage of ARID1A with intellectual disability and microcephaly.Genet Med advance online publication 01 December 2016.
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http://dx.doi.org/10.1038/gim.2016.180DOI Listing
June 2017

Study of myocardial cell inhomogeneity of the human heart: Simulation and validation using polarized light imaging.

Med Phys 2016 May;43(5):2273

CREATIS, CNRS UMR 5220, INSERM U1206, University of Lyon, INSA Lyon, Lyon 69621, France.

Purpose: The arrangement or architecture of myocardial cells plays a fundamental role in the heart's function and its change was shown to be directly linked to heart diseases. Inhomogeneity level is an important index of myocardial cell arrangements in the human heart. The authors propose to investigate the inhomogeneity level of myocardial cells using polarized light imaging simulations and experiments.

Methods: The idea is based on the fact that the myosin filaments in myocardial cells have the same properties as those of a uniaxial birefringent crystal. The method then consists in modeling the myosin filaments of myocardial cells as uniaxial birefringent crystal, simulating the behavior of the latter by means of the Mueller matrix, and measuring the final intensity of polarized light and consequently the inhomogeneity level of myocardial cells in each voxel through the use of crossed polarizers. The method was evaluated on both simulated and real tissues and under various myocardial cell configurations including parallel cells, crossed cells, and cells with random orientations.

Results: When myocardial cells run perfectly parallel to each other, all the polarized light was blocked by those parallel myocardial cells, and a high homogeneity level was observed. However, if myocardial cells were not parallel to each other, some leakage of the polarized light was observed, thus causing the decrease of the polarized light amplitude and homogeneity level. The greater the crossing angle between myocardial cells, the smaller the amplitude of the polarized light and the greater the inhomogeneity level. For two populations of myocardial cell crossing at an angle, the resulting azimuth angle of the voxel was the bisector of this angle. Moreover, the value of the inhomogeneity level began to decrease from a nonzero value when the voxel was not totally homogeneous, containing for example cell crossing.

Conclusions: The proposed method enables the physical information of myocardial tissues to be estimated and the inhomogeneity level of a volume or voxel to be quantified, which opens new ways to study the microstructures of the human myocardium and helps understanding how heart diseases modify myocardial cells and change their mechanical properties.
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http://dx.doi.org/10.1118/1.4945272DOI Listing
May 2016

Microdeletion del(22)(q12.1) excluding the MN1 gene in a patient with craniofacial anomalies.

Am J Med Genet A 2016 Feb 6;170A(2):498-503. Epub 2015 Nov 6.

Département de Génétique et Procréation, Hôpital Couple-Enfant, CHU de Grenoble, Grenoble, France.

Several studies have recently reported that 22q12.1 deletions encompassing the MN1 gene are associated with craniofacial anomalies. These observations are consistent with the hypothesis that MN1 haploinsufficiency may be solely responsible for craniofacial anomalies and/or cleft palate. We report here the case of a 4-year-old boy presenting with global developmental delay and craniofacial anomalies including severe maxillary protrusion and retromicrognathia. Array-CGH detected a 2.4 Mb de novo deletion of chromosome 22q12.1 which did not encompass the MN1 gene thought to be the main pathological candidate in 22q12.1 deletions. This observation, combined with data from other patients from the Database of Chromosomal Imbalance and Phenotype in Humans Using Ensemble Resources (DECIPHER), suggests that other gene(s) in the 22q12.1 region are likely involved in craniofacial anomalies and/or may contribute to the phenotypic variability observed in patients with MN1 deletion.
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http://dx.doi.org/10.1002/ajmg.a.37450DOI Listing
February 2016