Publications by authors named "Sophie Scheidecker"

21 Publications

  • Page 1 of 1

A BBS1 SVA F retrotransposon insertion is a frequent cause of Bardet-Biedl syndrome.

Clin Genet 2021 Feb 14;99(2):318-324. Epub 2020 Nov 14.

Laboratoire de Génétique Médicale, Institut de génétique médicale d'Alsace IGMA, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg UMRS_1112, Strasbourg, France.

Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinitis pigmentosa, obesity, polydactyly, cognitive impairment and renal failure. Pathogenic variants in 24 genes account for the molecular basis of >80% of cases. Toward saturated discovery of the mutational basis of the disorder, we carefully explored our cohorts and identified a hominid-specific SINE-R/VNTR/Alu type F (SVA-F) insertion in exon 13 of BBS1 in eight families. In six families, the repeat insertion was found in trans with c.1169 T > G, p.Met390Arg and in two families the insertion was found in addition to other recessive BBS loci. Whole genome sequencing, de novo assembly and SNP array analysis were performed to characterize the genomic event. This insertion is extremely rare in the general population (found in 8 alleles of 8 BBS cases but not in >10 800 control individuals from gnomAD-SV) and due to a founder effect. Its 2435 bp sequence contains hallmarks of LINE1 mediated retrotransposition. Functional studies with patient-derived cell lines confirmed that the BBS1 SVA-F is deleterious as evidenced by a significant depletion of both mRNA and protein levels. Such findings highlight the importance of dedicated bioinformatics pipelines to identify all types of variation.
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http://dx.doi.org/10.1111/cge.13878DOI Listing
February 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 Diagnostic Prénatal, Hôpital MFME, Fort de France, Martinique, 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

Proteasome subunit PSMC3 variants cause neurosensory syndrome combining deafness and cataract due to proteotoxic stress.

EMBO Mol Med 2020 07 5;12(7):e11861. Epub 2020 Jun 5.

Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.

The ubiquitin-proteasome system degrades ubiquitin-modified proteins to maintain protein homeostasis and to control signalling. Whole-genome sequencing of patients with severe deafness and early-onset cataracts as part of a neurological, sensorial and cutaneous novel syndrome identified a unique deep intronic homozygous variant in the PSMC3 gene, encoding the proteasome ATPase subunit Rpt5, which lead to the transcription of a cryptic exon. The proteasome content and activity in patient's fibroblasts was however unaffected. Nevertheless, patient's cells exhibited impaired protein homeostasis characterized by accumulation of ubiquitinated proteins suggesting severe proteotoxic stress. Indeed, the TCF11/Nrf1 transcriptional pathway allowing proteasome recovery after proteasome inhibition is permanently activated in the patient's fibroblasts. Upon chemical proteasome inhibition, this pathway was however impaired in patient's cells, which were unable to compensate for proteotoxic stress although a higher proteasome content and activity. Zebrafish modelling for knockout in PSMC3 remarkably reproduced the human phenotype with inner ear development anomalies as well as cataracts, suggesting that Rpt5 plays a major role in inner ear, lens and central nervous system development.
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http://dx.doi.org/10.15252/emmm.201911861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7338805PMC
July 2020

High prevalence of Bardet-Biedl syndrome in La Réunion Island is due to a founder variant in ARL6/BBS3.

Clin Genet 2020 08 22;98(2):166-171. Epub 2020 Jun 22.

Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.

Bardet-Biedl syndrome (BBS) is a rare ciliopathy with variable retinal dystrophy, polydactyly, renal abnormalities, obesity, cognitive impairment, and hypogonadism. Biallelic pathogenic variants have been identified in 24 genes, leading to BBS in an autosomal recessive inheritance pattern. In this study, we investigated a cohort of 16 families (20 individuals) presenting with typical BBS originating from La Réunion Island using sequencing (Sanger and high-throughput methods) and SNP array. In eight families (12 individuals) we identified the same ARL6/BBS3 variation [c.535G > A, p.(Asp179Asn)]. Bioinformatics and functional analyses revealed an effect of this variant on the splicing of ARL6/BBS3. Owing to the relatively high frequency of this variant, a possible founder effect was suspected. Genotyping of six individuals revealed a common 3.8-Mb haplotype and estimated the most recent common ancestor to about eight generations confirmed by the known genealogy. Knowledge of this founder effect modifies our diagnostic strategy and enables a personalized genetic counseling for patients from La Réunion Island. Being the first description of BBS patients from La Réunion Island, we could estimate its prevalence between ~1/45000 and ~ 1/66000 individuals.
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http://dx.doi.org/10.1111/cge.13768DOI Listing
August 2020

A severe case of Frank-ter Haar syndrome and literature review: Further delineation of the phenotypical spectrum.

Eur J Med Genet 2020 Apr 21;63(4):103857. Epub 2020 Jan 21.

Service de génétique médicale, Institut de Génétique Médicale d'Alsace (IGMA), Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Strasbourg, France. Electronic address:

Frank-ter Haar syndrome (FTHS) is a rare autosomal recessive syndrome resulting from mutations in the SH3PXD2B gene involved in the formation of podosomes and invadopodia which have a role in extracellular matrix remodelling and cell migration. FTHS is characterized by facial dysmorphism, megalocornea, inconstant glaucoma, variable developmental delay, skeletal and cardiac anomalies. To date, 40 patients have been reported in the literature with a clinical diagnosis of FTHS, only 20 patients having identified mutations. We present a review of these 20 reported patients and describe a patient born to non-consanguineous parents, with intrauterine growth retardation, hypotonia, congenital glaucoma, caudal appendix, scoliosis, camptodactyly, ventricular septal defect, thin corpus callosum and craniofacial features suggestive of FTHS. Clinical evolution resulted in buphthalmos worsening, coarsening of the facial features and respiratory failure leading to death at 4,5 months. Diagnosis was confirmed by the identification of a previously known homozygous mutation c.969delG, p.(Arg324Glyfs*19) in SH3PXD2B. This is the first description of very severe phenotype with lethal respiratory impairment in FTHS. Since very few patients are described in the literature, and 2 out of the 3 patients carrying the c.969delG mutation had a favourable clinical course, more cases are needed to better characterize the phenotype and understand the natural history of this syndrome. Furthermore, we hypothesize that the alteration of podosomes function could lead to a reduction of the extracellular matrix degradation and accumulation of the latter in the extracellular space, which might explain the coarsening of the facial features and the severe refractory glaucoma.
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http://dx.doi.org/10.1016/j.ejmg.2020.103857DOI Listing
April 2020

Novel IQCE variations confirm its role in postaxial polydactyly and cause ciliary defect phenotype in zebrafish.

Hum Mutat 2020 01 17;41(1):240-254. Epub 2019 Oct 17.

Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine, FMTS, Université de Strasbourg, Strasbourg, France.

Polydactyly is one of the most frequent inherited defects of the limbs characterized by supernumerary digits and high-genetic heterogeneity. Among the many genes involved, either in isolated or syndromic forms, eight have been implicated in postaxial polydactyly (PAP). Among those, IQCE has been recently identified in a single consanguineous family. Using whole-exome sequencing in patients with uncharacterized ciliopathies, including PAP, we identified three families with biallelic pathogenic variations in IQCE. Interestingly, the c.895_904del (p.Val301Serfs*8) was found in all families without sharing a common haplotype, suggesting a recurrent mechanism. Moreover, in two families, the systemic phenotype could be explained by additional pathogenic variants in known genes (TULP1, ATP6V1B1). RNA expression analysis on patients' fibroblasts confirms that the dysfunction of IQCE leads to the dysregulation of genes associated with the hedgehog-signaling pathway, and zebrafish experiments demonstrate a full spectrum of phenotypes linked to defective cilia: Body curvature, kidney cysts, left-right asymmetry, misdirected cilia in the pronephric duct, and retinal defects. In conclusion, we identified three additional families confirming IQCE as a nonsyndromic PAP gene. Our data emphasize the importance of taking into account the complete set of variations of each individual, as each clinical presentation could finally be explained by multiple genes.
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http://dx.doi.org/10.1002/humu.23924DOI Listing
January 2020

Clinical, histological, and genetic characterization of PYROXD1-related myopathy.

Acta Neuropathol Commun 2019 08 27;7(1):138. Epub 2019 Aug 27.

Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 1 rue Laurent Fries, 67404, Illkirch, France.

Recessive mutations in PYROXD1, encoding an oxidoreductase, were recently reported in families with congenital myopathy or limb-girdle muscular dystrophy. Here we describe three novel PYROXD1 families at the clinical, histological, and genetic level. Histological analyses on muscle biopsies from all families revealed fiber size variability, endomysial fibrosis, and muscle fibers with multiple internal nuclei and cores. Further characterization of the structural muscle defects uncovered aggregations of myofibrillar proteins, and provided evidence for enhanced oxidative stress. Sequencing identified homozygous or compound heterozygous PYROXD1 mutations including the first deep intronic mutation reinforcing a cryptic donor splice site and resulting in mRNA instability through exonisation of an intronic segment. Overall, this work expands the PYROXD1 mutation spectrum, defines and specifies the histopathological hallmarks of the disorder, and indicates that oxidative stress contributes to the pathomechanism. Comparison of all new and published cases uncovered a genotype/phenotype correlation with a more severe and early-onset phenotypic presentation of patients harboring splice mutations resulting in reduced PYROXD1 protein levels compared with patients carrying missense mutations.
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http://dx.doi.org/10.1186/s40478-019-0781-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6710884PMC
August 2019

Mutations in KARS cause a severe neurological and neurosensory disease with optic neuropathy.

Hum Mutat 2019 10 18;40(10):1826-1840. Epub 2019 Jun 18.

Laboratoire de Génétique Médicale, INSERM U1112, Institut de Génétique Médicale d'Alsace, Université de Strasbourg, Strasbourg, France.

Mutations in genes encoding aminoacyl-tRNA synthetases have been reported in several neurological disorders. KARS is a dual localized lysyl-tRNA synthetase and its cytosolic isoform belongs to the multiple aminoacyl-tRNA synthetase complex (MSC). Biallelic mutations in the KARS gene were described in a wide phenotypic spectrum ranging from nonsyndromic deafness to complex impairments. Here, we report on a patient with severe neurological and neurosensory disease investigated by whole-exome sequencing and found to carry biallelic mutations c.683C>T (p.Pro228Leu) and c.871T>G (p.Phe291Val), the second one being novel, in the KARS gene. The patient presented with an atypical clinical presentation with an optic neuropathy not previously reported. At the cellular level, we show that cytoplasmic KARS was expressed at a lower level in patient cells and displayed decreased interaction with MSC. In vitro, these two KARS variants have a decreased aminoacylation activity compared with wild-type KARS, the p.Pro228Leu being the most affected. Our data suggest that dysfunction of cytoplasmic KARS resulted in a decreased level of translation of the nuclear-encoded lysine-rich proteins belonging to the respiratory chain complex, thus impairing mitochondria functions.
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http://dx.doi.org/10.1002/humu.23799DOI Listing
October 2019

HCN1 mutation spectrum: from neonatal epileptic encephalopathy to benign generalized epilepsy and beyond.

Brain 2018 11;141(11):3160-3178

EuroEPINOMICS RES Consortium.

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control neuronal excitability and their dysfunction has been linked to epileptogenesis but few individuals with neurological disorders related to variants altering HCN channels have been reported so far. In 2014, we described five individuals with epileptic encephalopathy due to de novo HCN1 variants. To delineate HCN1-related disorders and investigate genotype-phenotype correlations further, we assembled a cohort of 33 unpublished patients with novel pathogenic or likely pathogenic variants: 19 probands carrying 14 different de novo mutations and four families with dominantly inherited variants segregating with epilepsy in 14 individuals, but not penetrant in six additional individuals. Sporadic patients had epilepsy with median onset at age 7 months and in 36% the first seizure occurred during a febrile illness. Overall, considering familial and sporadic patients, the predominant phenotypes were mild, including genetic generalized epilepsies and genetic epilepsy with febrile seizures plus (GEFS+) spectrum. About 20% manifested neonatal/infantile onset otherwise unclassified epileptic encephalopathy. The study also included eight patients with variants of unknown significance: one adopted patient had two HCN1 variants, four probands had intellectual disability without seizures, and three individuals had missense variants inherited from an asymptomatic parent. Of the 18 novel pathogenic missense variants identified, 12 were associated with severe phenotypes and clustered within or close to transmembrane domains, while variants segregating with milder phenotypes were located outside transmembrane domains, in the intracellular N- and C-terminal parts of the channel. Five recurrent variants were associated with similar phenotypes. Using whole-cell patch-clamp, we showed that the impact of 12 selected variants ranged from complete loss-of-function to significant shifts in activation kinetics and/or voltage dependence. Functional analysis of three different substitutions altering Gly391 revealed that these variants had different consequences on channel biophysical properties. The Gly391Asp variant, associated with the most severe, neonatal phenotype, also had the most severe impact on channel function. Molecular dynamics simulation on channel structure showed that homotetramers were not conducting ions because the permeation path was blocked by cation(s) strongly complexed to the Asp residue, whereas heterotetramers showed an instantaneous current component possibly linked to deformation of the channel pore. In conclusion, our results considerably expand the clinical spectrum related to HCN1 variants to include common generalized epilepsy phenotypes and further illustrate how HCN1 has a pivotal function in brain development and control of neuronal excitability.
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http://dx.doi.org/10.1093/brain/awy263DOI Listing
November 2018

Whole-genome sequencing in patients with ciliopathies uncovers a novel recurrent tandem duplication in IFT140.

Hum Mutat 2018 07 8;39(7):983-992. Epub 2018 May 8.

Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France.

Ciliopathies represent a wide spectrum of rare diseases with overlapping phenotypes and a high genetic heterogeneity. Among those, IFT140 is implicated in a variety of phenotypes ranging from isolated retinis pigmentosa to more syndromic cases. Using whole-genome sequencing in patients with uncharacterized ciliopathies, we identified a novel recurrent tandem duplication of exon 27-30 (6.7 kb) in IFT140, c.3454-488_4182+2588dup p.(Tyr1152_Thr1394dup), missed by whole-exome sequencing. Pathogenicity of the mutation was assessed on the patients' skin fibroblasts. Several hundreds of patients with a ciliopathy phenotype were screened and biallelic mutations were identified in 11 families representing 12 pathogenic variants of which seven are novel. Among those unrelated families especially with a Mainzer-Saldino syndrome, eight carried the same tandem duplication (two at the homozygous state and six at the heterozygous state). In conclusion, we demonstrated the implication of structural variations in IFT140-related diseases expanding its mutation spectrum. We also provide evidences for a unique genomic event mediated by an Alu-Alu recombination occurring on a shared haplotype. We confirm that whole-genome sequencing can be instrumental in the ability to detect structural variants for genomic disorders.
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http://dx.doi.org/10.1002/humu.23539DOI Listing
July 2018

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

Authors:
Marguerite Miguet Laurence Faivre Jeanne Amiel Mathilde Nizon Renaud Touraine Fabienne Prieur Laurent Pasquier Mathilde Lefebvre Julien Thevenon Christèle Dubourg Sophie Julia Catherine Sarret Ganaëlle Remerand Christine Francannet Fanny Laffargue Odile Boespflug-Tanguy Albert David Bertrand Isidor Jacqueline Vigneron Bruno Leheup Laetitia Lambert Christophe Philippe Mylène Béri-Dexheimer Jean-Marie Cuisset Joris Andrieux Ghislaine Plessis Annick Toutain Laurent Guibaud Valérie Cormier-Daire Marlene Rio Jean-Paul Bonnefont Bernard Echenne Hubert Journel Lydie Burglen Sandrine Chantot-Bastaraud Thierry Bienvenu Clarisse Baumann Laurence Perrin Séverine Drunat Pierre-Simon Jouk Klaus Dieterich Françoise Devillard Didier Lacombe Nicole Philip Sabine Sigaudy Anne Moncla Chantal Missirian Catherine Badens Nathalie Perreton Christel Thauvin-Robinet Réseau AChro-Puce Jean-Michel Pedespan Caroline Rooryck Cyril Goizet Catherine Vincent-Delorme Bénédicte Duban-Bedu Nadia Bahi-Buisson Alexandra Afenjar Kim Maincent Delphine Héron Jean-Luc Alessandri Dominique Martin-Coignard Gaëtan Lesca Massimiliano Rossi Martine Raynaud Patrick Callier Anne-Laure Mosca-Boidron Nathalie Marle Charles Coutton Véronique Satre Cédric Le Caignec Valérie Malan Serge Romana Boris Keren Anne-Claude Tabet Valérie Kremer Sophie Scheidecker Adeline Vigouroux Marilyn Lackmy-Port-Lis Damien Sanlaville Marianne Till Maryline Carneiro Brigitte Gilbert-Dussardier Marjolaine Willems Hilde Van Esch Vincent Des Portes Salima El Chehadeh

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

Service de génétique médicale, Institut de Génétique Médicale d'Alsace (IGMA), Centre de Référence Maladies Rares "Anomalies du développement et syndromes malformatifs", Centre de Référence Maladies Rares "Des déficiences intellectuelles de causes rares", Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Strasbourg, 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

9q22.3 Microdeletion Syndrome with Multiple Basal Cell Carcinomas Treated with Vismodegib: Three Key Messages in One Patient.

Acta Derm Venereol 2018 Feb;98(2):287-288

Department of Dermatology, Faculty of Medicine, University Hospital, University of Strasbourg, Hôpital Civil, 1 Place de l'Hôpital, FR-67000 Strasbourg, France.

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http://dx.doi.org/10.2340/00015555-2822DOI Listing
February 2018

Affected female carriers of MTM1 mutations display a wide spectrum of clinical and pathological involvement: delineating diagnostic clues.

Acta Neuropathol 2017 Dec 6;134(6):889-904. Epub 2017 Jul 6.

Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.

X-linked myotubular myopathy (XLMTM), a severe congenital myopathy, is caused by mutations in the MTM1 gene located on the X chromosome. A majority of affected males die in the early postnatal period, whereas female carriers are believed to be usually asymptomatic. Nevertheless, several affected females have been reported. To assess the phenotypic and pathological spectra of carrier females and to delineate diagnostic clues, we characterized 17 new unrelated affected females and performed a detailed comparison with previously reported cases at the clinical, muscle imaging, histological, ultrastructural and molecular levels. Taken together, the analysis of this large cohort of 43 cases highlights a wide spectrum of clinical severity ranging from severe neonatal and generalized weakness, similar to XLMTM male, to milder adult forms. Several females show a decline in respiratory function. Asymmetric weakness is a noteworthy frequent specific feature potentially correlated to an increased prevalence of highly skewed X inactivation. Asymmetry of growth was also noted. Other diagnostic clues include facial weakness, ptosis and ophthalmoplegia, skeletal and joint abnormalities, and histopathological signs that are hallmarks of centronuclear myopathy such as centralized nuclei and necklace fibers. The histopathological findings also demonstrate a general disorganization of muscle structure in addition to these specific hallmarks. Thus, MTM1 mutations in carrier females define a specific myopathy, which may be independent of the presence of an XLMTM male in the family. As several of the reported affected females carry large heterozygous MTM1 deletions not detectable by Sanger sequencing, and as milder phenotypes present as adult-onset limb-girdle myopathy, the prevalence of this myopathy is likely to be greatly underestimated. This report should aid diagnosis and thus the clinical management and genetic counseling of MTM1 carrier females. Furthermore, the clinical and pathological history of this cohort may be useful for therapeutic projects in males with XLMTM, as it illustrates the spectrum of possible evolution of the disease in patients surviving long term.
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http://dx.doi.org/10.1007/s00401-017-1748-0DOI Listing
December 2017

Genetic and phenotypic dissection of 1q43q44 microdeletion syndrome and neurodevelopmental phenotypes associated with mutations in ZBTB18 and HNRNPU.

Hum Genet 2017 04 10;136(4):463-479. Epub 2017 Mar 10.

AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Département de Génétique, 75013, Paris, France.

Subtelomeric 1q43q44 microdeletions cause a syndrome associating intellectual disability, microcephaly, seizures and anomalies of the corpus callosum. Despite several previous studies assessing genotype-phenotype correlations, the contribution of genes located in this region to the specific features of this syndrome remains uncertain. Among those, three genes, AKT3, HNRNPU and ZBTB18 are highly expressed in the brain and point mutations in these genes have been recently identified in children with neurodevelopmental phenotypes. In this study, we report the clinical and molecular data from 17 patients with 1q43q44 microdeletions, four with ZBTB18 mutations and seven with HNRNPU mutations, and review additional data from 37 previously published patients with 1q43q44 microdeletions. We compare clinical data of patients with 1q43q44 microdeletions with those of patients with point mutations in HNRNPU and ZBTB18 to assess the contribution of each gene as well as the possibility of epistasis between genes. Our study demonstrates that AKT3 haploinsufficiency is the main driver for microcephaly, whereas HNRNPU alteration mostly drives epilepsy and determines the degree of intellectual disability. ZBTB18 deletions or mutations are associated with variable corpus callosum anomalies with an incomplete penetrance. ZBTB18 may also contribute to microcephaly and HNRNPU to thin corpus callosum, but with a lower penetrance. Co-deletion of contiguous genes has additive effects. Our results confirm and refine the complex genotype-phenotype correlations existing in the 1qter microdeletion syndrome and define more precisely the neurodevelopmental phenotypes associated with genetic alterations of AKT3, ZBTB18 and HNRNPU in humans.
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http://dx.doi.org/10.1007/s00439-017-1772-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5360844PMC
April 2017

A mutation in VPS15 (PIK3R4) causes a ciliopathy and affects IFT20 release from the cis-Golgi.

Nat Commun 2016 11 24;7:13586. Epub 2016 Nov 24.

Medical Genetics Laboratory, INSERM U1112, Institute of Medical Genetics of Alsace, University of Strasbourg, Strasbourg Medical School, 67000 Strasbourg, France.

Ciliopathies are a group of diseases that affect kidney and retina among other organs. Here, we identify a missense mutation in PIK3R4 (phosphoinositide 3-kinase regulatory subunit 4, named VPS15) in a family with a ciliopathy phenotype. Besides being required for trafficking and autophagy, we show that VPS15 regulates primary cilium length in human fibroblasts, as well as ciliary processes in zebrafish. Furthermore, we demonstrate its interaction with the golgin GM130 and its localization to the Golgi. The VPS15-R998Q patient mutation impairs Golgi trafficking functions in humanized yeast cells. Moreover, in VPS15-R998Q patient fibroblasts, the intraflagellar transport protein IFT20 is not localized to vesicles trafficking to the cilium but is restricted to the Golgi. Our findings suggest that at the Golgi, VPS15 and GM130 form a protein complex devoid of VPS34 to ensure the IFT20-dependent sorting and transport of membrane proteins from the cis-Golgi to the primary cilium.
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http://dx.doi.org/10.1038/ncomms13586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123056PMC
November 2016

Prenatal diagnosis of focal dermal hypoplasia: Report of three fetuses and review of the literature.

Am J Med Genet A 2017 Feb 13;173(2):479-486. Epub 2016 Sep 13.

Faculté de Médecine de Strasbourg, Strasbourg, France.

Focal dermal hypoplasia (FDH) is a rare syndrome characterized by pleiotropic features knowing to involve mostly skin and limbs. Although FDH has been described in children and adults, the cardinal signs of the fetal phenotype are not straightforward impacting the quality of the prenatal diagnosis. We describe in depth the ultrasound, radiological, macroscopical, and histological phenotype of three female fetuses with a severe form of FDH, propose a review of the literature and an attempt to delineate minimal and cardinal signs for FDH diagnosis. This report confirms the variability of FDH phenotype, highlights unreported FDH features, and allows delineating evocative clinical associations for prenatal diagnosis, namely intrauterine growth retardation, limbs malformations, anterior wall/diaphragm defects, and eye anomalies. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajmg.a.37974DOI Listing
February 2017

Identification of a novel mutation confirms the implication of IFT172 (BBS20) in Bardet-Biedl syndrome.

J Hum Genet 2016 May 14;61(5):447-50. Epub 2016 Jan 14.

Laboratoire de Génétique Médicale, Institut de Génétique Médicale d'Alsace, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.

Bardet-Biedl syndrome (BBS; MIM 209900) is a recessive heterogeneous ciliopathy characterized by retinitis pigmentosa (RP), postaxial polydactyly, obesity, hypogonadism, cognitive impairment and kidney dysfunction. So far, 20 BBS genes have been identified, with the last reported ones being found in one or very few families. Whole-exome sequencing was performed in a consanguineous family in which two affected children presented typical BBS features (retinitis pigmentosa, postaxial polydactyly, obesity, hypogonadism and cognitive impairment) without any mutation identified in known BBS genes at the time of the study. We identified a homozygous splice-site mutation (NM_015662.2: c.4428+3A>G) in both affected siblings in the last reported BBS gene, namely, Intraflagellar Transport 172 Homolog (IFT172). Familial mutation segregation was consistent with autosomal recessive inheritance. IFT172 mutations were initially reported in Jeune and Mainzer-Saldino syndromes. Recently, mutations have also been found in isolated RP and Bardet-Biedl-like ciliopathy. This is the second report of IFT172 mutations in BBS patients validating IFT172 as the twentieth BBS gene (BBS20). Moreover, another IFT gene, IFT27, was already associated with BBS, confirming the implication of IFT genes in the pathogenesis of BBS.
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http://dx.doi.org/10.1038/jhg.2015.162DOI Listing
May 2016

Long term follow up of two independent patients with Schinzel-Giedion carrying SETBP1 mutations.

Eur J Med Genet 2015 Sep 15;58(9):479-87. Epub 2015 Jul 15.

Laboratoire de Génétique Médicale INSERM U1112, Institut de Génétique Médicale d'Alsace (IGMA), Faculté de Médecine de Strasbourg, Université De Strasbourg, Strasbourg, France; Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), Hôpitaux Universitaires de Strasbourg, Strasbourg, France; Service de Génétique Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France. Electronic address:

Schinzel-Giedion syndrome (SGS, MIM #269150) is a rare syndrome characterized by severe intellectual disability, typical facial gestalt, hypertrichosis and multiple congenital malformations including skeletal, genitourinary, renal and cardiac abnormalities. The prognosis of SGS is very severe and death occurs generally within a few years after birth. In 2002, we reported 2 children with SGS with a follow-up of 3 years. They presented a very similar and particular phenotype associating distinctive facial gestalt, severe developmental delay, megacalycosis, progressive neurodegeneration, alacrimi, corneal hypoesthesia and deafness. Furthermore, temporal bone imaging revealed a tuning-fork malformation of the stapes. In 2010, Hoischen et al. identified in SGS patients pathogenic heterozygous de novo mutations in SETBP1. We sequenced SETBP1 in our patients and found the previously reported c.2608G>A (p.Gly870Ser) mutation in both children. Since 2002, one of our patients died at 6 years old and the other patient is still alive at 15 years old. Such a life expectancy has never been reported so far. We describe herein the follow up of the 2 children during 6 and 15 years respectively. This article gives further evidence of the implication of SETBP1 as the major gene of SGS, and reports the previously unseen natural evolution of the disease in a 15 years old patient.
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http://dx.doi.org/10.1016/j.ejmg.2015.07.004DOI Listing
September 2015

Predominantly Cone-System Dysfunction as Rare Form of Retinal Degeneration in Patients With Molecularly Confirmed Bardet-Biedl Syndrome.

Am J Ophthalmol 2015 Aug 15;160(2):364-372.e1. Epub 2015 May 15.

Service de Génétique Médicale, Institut de Génétique Médicale d'Alsace, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), Strasbourg, France; Laboratoire de Génétique Médicale, Institut de Génétique Médicale d'Alsace, INSERM U1112, Faculté de Médecine, Université de Strasbourg, Strasbourg, France. Electronic address:

Purpose: To describe a series of patients with Bardet-Biedl syndrome (BBS) and predominantly retinal cone dysfunction, a previously only rarely reported association.

Design: Retrospective observational case series.

Methods: Seven patients with clinically proven Bardet-Biedl syndrome had undergone detailed ocular phenotyping, which included fundus examination, Goldmann visual fields, fundus autofluorescence imaging (FAF), optical coherence tomography (OCT), and electroretinography (ERG). Mutational screening in the BBS genes was performed either by direct Sanger sequencing or targeted next-generation sequencing.

Results: All 7 patients had proven BBS mutations; 1 had a cone dystrophy phenotype on ERG and 6 had a cone-rod pattern of dysfunction. Macular atrophy was present in all patients, usually with central hypofluorescence surrounded by a continuous hyperfluorescent ring on fundus autofluorescence imaging. OCT confirmed loss of outer retinal structure within the atrophic areas. No clear genotype-phenotype relationship was evident.

Conclusions: Patients with Bardet-Biedl syndrome usually develop early-onset retinitis pigmentosa. In contrast, the patients described herein, with molecularly confirmed Bardet-Biedl syndrome, developed early cone dysfunction, including the first reported case of a cone dystrophy phenotype associated with the disorder. The findings significantly expand the phenotype associated with Bardet-Biedl syndrome.
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http://dx.doi.org/10.1016/j.ajo.2015.05.007DOI Listing
August 2015

Mutations in TUBGCP4 alter microtubule organization via the γ-tubulin ring complex in autosomal-recessive microcephaly with chorioretinopathy.

Am J Hum Genet 2015 Apr 26;96(4):666-74. Epub 2015 Mar 26.

Medical Genetics Laboratory, INSERM U1112, Institute of Genetics and Medicine of Alsace, Strasbourg Medical School, University of Strasbourg, 67085 Strasbourg, France; Centre de Référence National pour les Affections Rares en Génétique Ophtalmologique, Hôpitaux Universitaires de Strasbourg, 67091 Strasbourg, France. Electronic address:

We have identified TUBGCP4 variants in individuals with autosomal-recessive microcephaly and chorioretinopathy. Whole-exome sequencing performed on one family with two affected siblings and independently on another family with one affected child revealed compound-heterozygous mutations in TUBGCP4. Subsequent Sanger sequencing was performed on a panel of individuals from 12 French families affected by microcephaly and ophthalmic manifestations, and one other individual was identified with compound-heterozygous mutations in TUBGCP4. One synonymous variant was common to all three families and was shown to induce exon skipping; the other mutations were frameshift mutations and a deletion. TUBGCP4 encodes γ-tubulin complex protein 4, a component belonging to the γ-tubulin ring complex (γ-TuRC) and known to regulate the nucleation and organization of microtubules. Functional analysis of individual fibroblasts disclosed reduced levels of the γ-TuRC, altered nucleation and organization of microtubules, abnormal nuclear shape, and aneuploidy. Moreover, zebrafish treated with morpholinos against tubgcp4 were found to have reduced head volume and eye developmental anomalies with chorioretinal dysplasia. In summary, the identification of TUBGCP4 mutations in individuals with microcephaly and a spectrum of anomalies in eye development, particularly photoreceptor anomalies, provides evidence of an important role for the γ-TuRC in brain and eye development.
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http://dx.doi.org/10.1016/j.ajhg.2015.02.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4385181PMC
April 2015

Exome sequencing of Bardet-Biedl syndrome patient identifies a null mutation in the BBSome subunit BBIP1 (BBS18).

J Med Genet 2014 Feb 11;51(2):132-6. Epub 2013 Sep 11.

Laboratoire de Génétique Médicale, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France.

Background: Bardet-Biedl syndrome (BBS) is a recessive and genetically heterogeneous ciliopathy characterised by retinitis pigmentosa, obesity, kidney dysfunction, postaxial polydactyly, behavioural dysfunction and hypogonadism. 7 of the 17 BBS gene products identified to date assemble together with the protein BBIP1/BBIP10 into the BBSome, a protein complex that ferries signalling receptors to and from cilia.

Methods And Results: Exome sequencing performed on a sporadic BBS case revealed for the first time a homozygous stop mutation (NM_001195306: c.173T>G, p.Leu58*) in the BBIP1 gene. This mutation is pathogenic since no BBIP1 protein could be detected in fibroblasts from the patient, and BBIP1[Leu58*] is unable to associate with the BBSome subunit BBS4.

Conclusions: These findings identify BBIP1 as the 18th BBS gene (BBS18) and suggest that BBSome assembly may represent a unifying pathomechanism for BBS.
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http://dx.doi.org/10.1136/jmedgenet-2013-101785DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3966300PMC
February 2014