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Vaché C, Baux D, Bianchi J, Baudoin C, Faugère V, Francannet C, Koenig M, Kalatzis V, Roux AF. Reclassification of a TMC1 synonymous substitution as a variant disrupting splicing regulatory elements associated with recessive hearing loss. Eur J Hum Genet 2022; 30:34-41. [PMID: 34857896 PMCID: PMC8738754 DOI: 10.1038/s41431-021-01010-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 01/03/2023] Open
Abstract
Alterations of the transmembrane channel-like 1 gene (TMC1) are involved in autosomal recessive and dominant nonsyndromic hearing loss (NSHL). To date, up to 117 causal variants including substitutions, insertions and splice variants have been reported in families from different populations. In a patient suffering from severe prelingual NSHL, we identified, in the homozygous state, the previously considered likely benign synonymous c.627C>T; p.(Leu209=) substitution. We used in silico tools predicting variant-induced alterations of splicing regulatory elements (SREs) and pinpointed this transition as a candidate splice-altering variation. Functional splicing analysis, using a minigene assay, confirmed that the variant altered a critical regulatory sequence which is essential for the exon 11 inclusion in the TMC1 transcripts. This result was reinforced by the analysis of orthologous TMC1 mammalian sequences for which the deleterious effect on the mRNA processing of a native thymidine was always counteracted by the presence of a stronger donor splice site or additional enhancer motifs. This study demonstrates, for the first time, the pathogenicity of the c.627C>T alteration leading to its reclassification as a causal variant impacting SREs and highlights the major importance of exhaustive studies to accurately evaluate the pathogenicity of a variant, regardless of the variation type.
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Affiliation(s)
- Christel Vaché
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France ,grid.121334.60000 0001 2097 0141Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm, Montpellier, France
| | - David Baux
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France ,grid.121334.60000 0001 2097 0141Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm, Montpellier, France
| | - Julie Bianchi
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France
| | - Corinne Baudoin
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France
| | - Valérie Faugère
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France
| | - Christine Francannet
- grid.411163.00000 0004 0639 4151Department of Medical Genetics, Estaing Hospital, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Michel Koenig
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France
| | - Vasiliki Kalatzis
- grid.121334.60000 0001 2097 0141Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm, Montpellier, France
| | - Anne-Françoise Roux
- grid.157868.50000 0000 9961 060XMolecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France ,grid.121334.60000 0001 2097 0141Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm, Montpellier, France
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Mansard L, Baux D, Vaché C, Blanchet C, Meunier I, Willems M, Faugère V, Baudoin C, Moclyn M, Bianchi J, Dollfus H, Gilbert-Dussardier B, Dupin-Deguine D, Bonneau D, Drumare I, Odent S, Zanlonghi X, Claustres M, Koenig M, Kalatzis V, Roux AF. The Study of a 231 French Patient Cohort Significantly Extends the Mutational Spectrum of the Two Major Usher Genes MYO7A and USH2A. Int J Mol Sci 2021; 22:ijms222413294. [PMID: 34948090 PMCID: PMC8703989 DOI: 10.3390/ijms222413294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 01/06/2023] Open
Abstract
Usher syndrome is an autosomal recessive disorder characterized by congenital hearing loss combined with retinitis pigmentosa, and in some cases, vestibular areflexia. Three clinical subtypes are distinguished, and MYO7A and USH2A represent the two major causal genes involved in Usher type I, the most severe form, and type II, the most frequent form, respectively. Massively parallel sequencing was performed on a cohort of patients in the context of a molecular diagnosis to confirm clinical suspicion of Usher syndrome. We report here 231 pathogenic MYO7A and USH2A genotypes identified in 73 Usher type I and 158 Usher type II patients. Furthermore, we present the ACMG classification of the variants, which comprise all types. Among them, 68 have not been previously reported in the literature, including 12 missense and 16 splice variants. We also report a new deep intronic variant in USH2A. Despite the important number of molecular studies published on these two genes, we show that during the course of routine genetic diagnosis, undescribed variants continue to be identified at a high rate. This is particularly pertinent in the current era, where therapeutic strategies based on DNA or RNA technologies are being developed.
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Affiliation(s)
- Luke Mansard
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - David Baux
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, Inserm, F-34000 Montpellier, France; (I.M.); (M.W.); (V.K.)
| | - Christel Vaché
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, Inserm, F-34000 Montpellier, France; (I.M.); (M.W.); (V.K.)
| | - Catherine Blanchet
- National Reference Centre for Inherited Sensory Diseases, University Montpellier, CHU Montpellier, F-34000 Montpellier, France;
- Oto Laryngology Department, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, Inserm, F-34000 Montpellier, France; (I.M.); (M.W.); (V.K.)
- National Reference Centre for Inherited Sensory Diseases, University Montpellier, CHU Montpellier, F-34000 Montpellier, France;
| | - Marjolaine Willems
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, Inserm, F-34000 Montpellier, France; (I.M.); (M.W.); (V.K.)
- Medical Genetics Department, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France
| | - Valérie Faugère
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - Corinne Baudoin
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - Melody Moclyn
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - Julie Bianchi
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - Helene Dollfus
- Reference Center for Rare Affections in Ophthalmology Genetics (CARGO), Institute of Medical Genetics of Alsace, University of Strasbourg, CHU Strasbourg, F-67000 Strasbourg, France;
| | | | - Delphine Dupin-Deguine
- Medical Genetics Department, University of Toulouse, CHU Purpan, F-31000 Toulouse, France;
| | - Dominique Bonneau
- Medical Genetics Department, University of Angers, CHU Angers, F-49000 Angers, France;
| | - Isabelle Drumare
- Vision and Neuro-Ophthalmology Department, University of Lille, CHU Lille, F-59000 Lille, France;
| | - Sylvie Odent
- Clinical Genetics Service, University Hospital, Genetics and Development Institute of Rennes IDGDR, UMR6290 University of Rennes, F-35000 Rennes, France;
| | - Xavier Zanlonghi
- Center of Competence for Rare Diseases, Jules Verne Clinic, F-44000 Nantes, France;
| | - Mireille Claustres
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - Michel Koenig
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
| | - Vasiliki Kalatzis
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, Inserm, F-34000 Montpellier, France; (I.M.); (M.W.); (V.K.)
| | - Anne-Françoise Roux
- Molecular Genetics Laboratory, University of Montpellier, CHU Montpellier, F-34000 Montpellier, France; (L.M.); (D.B.); (C.V.); (V.F.); (C.B.); (M.M.); (J.B.); (M.C.); (M.K.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, Inserm, F-34000 Montpellier, France; (I.M.); (M.W.); (V.K.)
- Correspondence:
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Palagano E, Gordon CT, Uva P, Strina D, Dimartino C, Villa A, Amiel J, Guion-Almeida ML, Vendramini-Pittoli S, Kokitsu-Nakata NM, Zechi-Ceide RM, Sobacchi C. A novel intronic variant in PIGB in Acrofrontofacionasal dysostosis type 1 patients expands the spectrum of phenotypes associated with GPI biosynthesis defects. Bone 2021; 153:116152. [PMID: 34400385 DOI: 10.1016/j.bone.2021.116152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 11/15/2022]
Abstract
Acrofrontofacionasal dysostosis type 1 (AFFND1) is an extremely rare disorder characterized by several dysmorphic features, skeletal abnormalities and intellectual disability, and described only in seven patients in the literature. A biallelic variant in the Neuroblastoma Amplified Sequence (NBAS) gene was recently identified in two Indian patients with AFFND1. Here we report genetic investigation of AFFND1 in the originally described Brazilian families and the identification of an extremely rare, recessively-inherited, intronic variant in the Phosphatidylinositol Glycan class B (PIGB) gene NC_000015.10 (NM_004855.4): c.795-19T > G) in the affected individuals. The PIGB gene encodes an enzyme involved in the biosynthesis of the glycosylphosphatidylinositol (GPI) anchor, which is required for the post-translational modification of a large variety of proteins, enabling their correct cellular localization and function. Recessive variants in PIGB have previously been reported in individuals with a neurodevelopmental syndrome having partial overlap with AFFND1. In vitro assays demonstrated that the intronic variant leads to exon skipping, suggesting the Brazilian AFFND1 patients may be null for PIGB, in agreement with their severe clinical phenotype. These data increase the number of pathogenic variants in the PIGB gene, place AFFND1 among GPI deficiencies and extend the spectrum of phenotypes associated with GPI biosynthesis defects.
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Affiliation(s)
- Eleonora Palagano
- CNR-IRGB, Milan Unit, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano (MI), Italy
| | | | - Paolo Uva
- IRCCS G. Gaslini, Genoa, Italy; Italian Institute of Technology, Genoa, Italy
| | - Dario Strina
- CNR-IRGB, Milan Unit, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano (MI), Italy
| | | | - Anna Villa
- CNR-IRGB, Milan Unit, Milan, Italy; San Raffaele Telethon Institute for Gene Therapy SR-Tiget, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Jeanne Amiel
- INSERM UMR1163, Institut Imagine, Université de Paris, Paris, France; Service de Génétique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Maria L Guion-Almeida
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, Brazil
| | - Siulan Vendramini-Pittoli
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, Brazil
| | - Nancy M Kokitsu-Nakata
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, Brazil
| | - Roseli M Zechi-Ceide
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, Brazil
| | - Cristina Sobacchi
- CNR-IRGB, Milan Unit, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano (MI), Italy.
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A deep learning approach to identify gene targets of a therapeutic for human splicing disorders. Nat Commun 2021; 12:3332. [PMID: 34099697 PMCID: PMC8185002 DOI: 10.1038/s41467-021-23663-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/07/2021] [Indexed: 01/16/2023] Open
Abstract
Pre-mRNA splicing is a key controller of human gene expression. Disturbances in splicing due to mutation lead to dysregulated protein expression and contribute to a substantial fraction of human disease. Several classes of splicing modulator compounds (SMCs) have been recently identified and establish that pre-mRNA splicing represents a target for therapy. We describe herein the identification of BPN-15477, a SMC that restores correct splicing of ELP1 exon 20. Using transcriptome sequencing from treated fibroblast cells and a machine learning approach, we identify BPN-15477 responsive sequence signatures. We then leverage this model to discover 155 human disease genes harboring ClinVar mutations predicted to alter pre-mRNA splicing as targets for BPN-15477. Splicing assays confirm successful correction of splicing defects caused by mutations in CFTR, LIPA, MLH1 and MAPT. Subsequent validations in two disease-relevant cellular models demonstrate that BPN-15477 increases functional protein, confirming the clinical potential of our predictions.
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Morbidoni V, Baschiera E, Forzan M, Fumini V, Ali DS, Giorgi G, Buson L, Desbats MA, Cassina M, Clementi M, Salviati L, Trevisson E. Hybrid Minigene Assay: An Efficient Tool to Characterize mRNA Splicing Profiles of NF1 Variants. Cancers (Basel) 2021; 13:cancers13050999. [PMID: 33673681 PMCID: PMC7957615 DOI: 10.3390/cancers13050999] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 02/08/2023] Open
Abstract
Neurofibromatosis type 1 (NF1) is caused by heterozygous loss of function mutations in the NF1 gene. Although patients are diagnosed according to clinical criteria and few genotype-phenotype correlations are known, molecular analysis remains important. NF1 displays allelic heterogeneity, with a high proportion of variants affecting splicing, including deep intronic alleles and changes outside the canonical splice sites, making validation problematic. Next Generation Sequencing (NGS) technologies integrated with multiplex ligation-dependent probe amplification (MLPA) have largely overcome RNA-based techniques but do not detect splicing defects. A rapid minigene-based system was set up to test the effects of NF1 variants on splicing. We investigated 29 intronic and exonic NF1 variants identified in patients during the diagnostic process. The minigene assay showed the coexistence of multiple mechanisms of splicing alterations for seven variants. A leaky effect on splicing was documented in one de novo substitution detected in a sporadic patient with a specific phenotype without neurofibromas. Our splicing assay proved to be a reliable and fast method to validate novel NF1 variants potentially affecting splicing and to detect hypomorphic effects that might have phenotypic consequences, avoiding the requirement of patient's RNA.
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Affiliation(s)
- Valeria Morbidoni
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
- Istituto di Ricerca Pediatrica—IRP, Fondazione Città della Speranza, 35127 Padova, Italy
| | - Elisa Baschiera
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
- Istituto di Ricerca Pediatrica—IRP, Fondazione Città della Speranza, 35127 Padova, Italy
| | - Monica Forzan
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
| | - Valentina Fumini
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
| | - Dario Seif Ali
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
| | - Gianpietro Giorgi
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
| | - Lisa Buson
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
- Istituto di Ricerca Pediatrica—IRP, Fondazione Città della Speranza, 35127 Padova, Italy
| | - Maria Andrea Desbats
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
- Istituto di Ricerca Pediatrica—IRP, Fondazione Città della Speranza, 35127 Padova, Italy
| | - Matteo Cassina
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
| | - Maurizio Clementi
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
- Istituto di Ricerca Pediatrica—IRP, Fondazione Città della Speranza, 35127 Padova, Italy
| | - Eva Trevisson
- Clinical Genetics Unit, Department of Women’s and Children’s Health, University of Padova, 35128 Padova, Italy; (V.M.); (E.B.); (M.F.); (V.F.); (D.S.A.); (G.G.); (L.B.); (M.A.D.); (M.C.); (M.C.); (L.S.)
- Istituto di Ricerca Pediatrica—IRP, Fondazione Città della Speranza, 35127 Padova, Italy
- Correspondence: ; Tel.: + 39-(04)-9821-1402
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Wang C, Zhou W, Huang Y, Yin H, Jin Y, Jia Z, Zhang A, Liu Z, Zheng B. Presumed missense and synonymous mutations in ATP7B gene cause exon skipping in Wilson disease. Liver Int 2018; 38:1504-1513. [PMID: 29637721 DOI: 10.1111/liv.13754] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/28/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS Wilson disease is an inborn error of metabolism caused by abnormalities of the copper-transporting protein-encoding gene ATP7B. Recently, the phenomenon of exon skipping, in which exonic mutations result in abnormal splicing, has been associated with various diseases. The present study investigated the splicing defects of the ATP7B exonic variants identified in a cohort of 44 patients with Wilson disease. METHOD All patients were analysed for ATP7B gene by direct sequencing or multiplex ligation-dependent probe amplification analysis. To identify the potential pathogenicity of the candidate mutations that may induce exon skipping, both in vivo RT-PCR analysis using RNA from peripheral leukocytes and in vitro functional splicing by minigene construction were conducted. RESULTS The patterns of inheritance of the mutations in ATP7B identified in 44 patients exhibited homozygotes (7 patients), compound heterozygotes (32 patients) and heterozygotes (5 patients). In all patients, we detected 25 different ATP7B mutations, including 17 missenses, 1 frameshift, 3 nonsenses, 2 exonic deletions and 2 splicing alteration. In these mutations, 4 mutations have not been previously described in the literature or entered in human genome mutation database. Furthermore, we identified synonymous mutation c.4014T>A and missense mutation R919G caused exon skipping in the ATP7B mRNA transcript. CONCLUSION Our results suggest that aberrant exon skipping associated to putative splicing enhancer disruption and silencer creation is one previously unrecognized mechanism in Wilson disease. What is more, the multiplex ligation-dependent probe amplification assay for the detection of exon deletions may be valuable in individuals with clinical Wilson disease diagnosis where one or no mutation has been identified by sequencing.
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Affiliation(s)
- Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Zhou
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Yan Huang
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Hanjun Yin
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Yu Jin
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Aihua Zhang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhifeng Liu
- Department of Gastroenterology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
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7
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Clinical characteristics and NF1 gene mutation analysis of three successive generations in three different Indian families with neurofibromatosis type 1 and peripheral nerve sheath tumours. J Clin Neurosci 2018; 53:62-68. [PMID: 29680440 DOI: 10.1016/j.jocn.2018.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 03/05/2018] [Accepted: 04/02/2018] [Indexed: 11/21/2022]
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Shao L, Cui L, Lu J, Lang Y, Bottillo I, Zhao X. A novel mutation in exon 9 of Cullin 3 gene contributes to aberrant splicing in pseudohypoaldosteronism type II. FEBS Open Bio 2018; 8:461-469. [PMID: 29511623 PMCID: PMC5832971 DOI: 10.1002/2211-5463.12389] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/26/2017] [Accepted: 01/12/2018] [Indexed: 01/30/2023] Open
Abstract
Pseudohypoaldosteronism type II (PHAII) is a rare renal tubular disease that is inherited in an autosomal dominant manner. Mutations in four genes (WNK1,WNK4,CUL3, and KLHL3) have been identified to be responsible for this disease. Cullin 3 (CUL3) and KLHL3 are subunits of Cullin–RING E3 ubiquitin ligase complexes, and the serine–threonine kinases WNK1 and WNK4 are substrates of this ubiquitin ligase. For CUL3, all mutations associated with PHAII exclusively lead to exon 9 skipping. In this study, we identified a Chinese PHAII kindred caused by a novel synonymous mutation (c.1221A > G p.Glu407Glu) in CUL3, and explored its effects on exon 9 abnormal splicing through an in vitro splicing assay and study of the patients’ RNA. We obtained evidence that this synonymous mutation leads to complete exon 9 skipping, and in silico bioinformatics analysis demonstrated that the CUL3 c.1221A > G mutation might decrease the ratio of exonic splicing enhancers and silencers. This is the first report of PHAII in Chinese patients with a novel CUL3 mutation. Our findings add a novel pathogenic splicing variant to the CUL3 mutational spectrum and provide reference for further research on mechanisms of splicing modulation and development of potential therapeutic reagents for PHAII.
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Affiliation(s)
- Leping Shao
- Department of Nephrology The Affiliated Hospital of Qingdao University Qingdao China
| | - Li Cui
- Department of Nephrology The Affiliated Hospital of Qingdao University Qingdao China
| | - Jingru Lu
- Department of Nephrology The Affiliated Hospital of Qingdao University Qingdao China
| | - Yanhua Lang
- Department of Nephrology The Affiliated Hospital of Qingdao University Qingdao China
| | - Irene Bottillo
- Division of Medical Genetics Department of Molecular Medicine Sapienza University San Camillo-Forlanini Hospital Rome Italy
| | - Xiangzhong Zhao
- Central Laboratory The Affiliated Hospital of Qingdao University Qingdao China
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9
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Villate O, Ibarluzea N, Fraile-Bethencourt E, Valenzuela A, Velasco EA, Grozeva D, Raymond FL, Botella MP, Tejada MI. Functional Analyses of a Novel Splice Variant in the CHD7 Gene, Found by Next Generation Sequencing, Confirm Its Pathogenicity in a Spanish Patient and Diagnose Him with CHARGE Syndrome. Front Genet 2018; 9:7. [PMID: 29434620 PMCID: PMC5790995 DOI: 10.3389/fgene.2018.00007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/08/2018] [Indexed: 01/30/2023] Open
Abstract
Mutations in CHD7 have been shown to be a major cause of CHARGE syndrome, which presents many symptoms and features common to other syndromes making its diagnosis difficult. Next generation sequencing (NGS) of a panel of intellectual disability related genes was performed in an adult patient without molecular diagnosis. A splice donor variant in CHD7 (c.5665 + 1G > T) was identified. To study its potential pathogenicity, exons and flanking intronic sequences were amplified from patient DNA and cloned into the pSAD® splicing vector. HeLa cells were transfected with this construct and a wild-type minigene and functional analysis were performed. The construct with the c.5665 + 1G > T variant produced an aberrant transcript with an insert of 63 nucleotides of intron 28 creating a premature termination codon (TAG) 25 nucleotides downstream. This would lead to the insertion of 8 new amino acids and therefore a truncated 1896 amino acid protein. As a result of this, the patient was diagnosed with CHARGE syndrome. Functional analyses underline their usefulness for studying the pathogenicity of variants found by NGS and therefore its application to accurately diagnose patients.
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Affiliation(s)
- Olatz Villate
- Biocruces Health Research Institute, Barakaldo, Spain.,Molecular Genetics Laboratory, Genetics Service, Cruces University Hospital, Barakaldo, Spain
| | | | - Eugenia Fraile-Bethencourt
- Splicing and Cancer Laboratory, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Alberto Valenzuela
- Splicing and Cancer Laboratory, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Eladio A Velasco
- Splicing and Cancer Laboratory, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Detelina Grozeva
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - F L Raymond
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - María P Botella
- Department of Pediatrics, Araba University Hospital, Vitoria, Spain
| | - María-Isabel Tejada
- Biocruces Health Research Institute, Barakaldo, Spain.,Molecular Genetics Laboratory, Genetics Service, Cruces University Hospital, Barakaldo, Spain.,Clinical Group, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
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10
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Zhao X, Cui L, Lang Y, Liu T, Lu J, Wang C, Tuffery-Giraud S, Bottillo I, Wang X, Shao L. A recurrent deletion in the SLC5A2 gene including the intron 7 branch site responsible for familial renal glucosuria. Sci Rep 2016; 6:33920. [PMID: 27666404 PMCID: PMC5036194 DOI: 10.1038/srep33920] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022] Open
Abstract
Familial renal glycosuria (FRG) is caused by mutations in the SLC5A2 gene, which codes for Na+-glucose co-transporters 2 (SGLT2). The aim of this study was to analyze and identify the mutations in 16 patients from 8 families with FRG. All coding regions, including intron-exon boundaries, were analyzed using PCR followed by direct sequence analysis. Six mutations in SLC5A2 gene were identified, including five missense mutations (c.393G > C, p.K131N; c.1003A > G, p.S335G; c.1343A > G, p.Q448R; c.1420G > C, p.A474P; c.1739G > A, p.G580D) and a 22-bp deletion in intron 7 (c.886(-10_-31)del) removing the putative branch point sequence. By the minigene studies using the pSPL3 plasmids, we confirmed that the deletion c.886(-10_-31)del acts as a splicing mutation. Furthermore, we found that this deletion causes exclusion of exon 8 in the SCL5A2 transcript in patients. The mutation c.886(-10_-31)del was present in 5 (62.5%) of 8 families, and accounts for about 37.5% of the total alleles (6/16). In conclusion, six mutations resulting in FRG were found, and the c.886(-10_-31)del may be the high frequency mutation that can be screened in FRG patients with uniallelic or negative SLC5A2 mutations.
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Affiliation(s)
- Xiangzhong Zhao
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China
| | - Li Cui
- Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Yanhua Lang
- Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Ting Liu
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Jingru Lu
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Cui Wang
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Sylvie Tuffery-Giraud
- Laboratory of Genetics of Rare Diseases, EA7402, University of Montpellier, F-34000, France
| | - Irene Bottillo
- Division of Medical Genetics, Department of Molecular Medicine, Sapienza University, San Camillo-Forlanini Hospital, Circ. Gianicolense, 87, Padiglione Morgagni 00152, Rome, Italy
| | - Xinsheng Wang
- Urology, Affiliated Hospital, Qingdao University, Qingdao 266003, China
| | - Leping Shao
- Central Laboratory, The Affiliated Hospital of Qingdao University, 1677 Wutaishan Road, Qingdao 266555, China.,Department of Nephrology, the Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
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11
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Liquori A, Vaché C, Baux D, Blanchet C, Hamel C, Malcolm S, Koenig M, Claustres M, Roux AF. Whole USH2A Gene Sequencing Identifies Several New Deep Intronic Mutations. Hum Mutat 2015; 37:184-93. [PMID: 26629787 DOI: 10.1002/humu.22926] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/19/2015] [Indexed: 01/01/2023]
Abstract
Deep intronic mutations leading to pseudoexon (PE) insertions are underestimated and most of these splicing alterations have been identified by transcript analysis, for instance, the first deep intronic mutation in USH2A, the gene most frequently involved in Usher syndrome type II (USH2). Unfortunately, analyzing USH2A transcripts is challenging and for 1.8%-19% of USH2 individuals carrying a single USH2A recessive mutation, a second mutation is yet to be identified. We have developed and validated a DNA next-generation sequencing approach to identify deep intronic variants in USH2A and evaluated their consequences on splicing. Three distinct novel deep intronic mutations have been identified. All were predicted to affect splicing and resulted in the insertion of PEs, as shown by minigene assays. We present a new and attractive strategy to identify deep intronic mutations, when RNA analyses are not possible. Moreover, the bioinformatics pipeline developed is independent of the gene size, implying the possible application of this approach to any disease-linked gene. Finally, an antisense morpholino oligonucleotide tested in vitro for its ability to restore splicing caused by the c.9959-4159A>G mutation provided high inhibition rates, which are indicative of its potential for molecular therapy.
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Affiliation(s)
- Alessandro Liquori
- Laboratoire de Génétique de Maladies Rares EA 7402, Université de Montpellier, Montpellier, France
| | - Christel Vaché
- Laboratoire de Génétique de Maladies Rares EA 7402, Université de Montpellier, Montpellier, France.,Laboratoire de Génétique Moléculaire, CHRU Montpellier, Montpellier, France
| | - David Baux
- Laboratoire de Génétique de Maladies Rares EA 7402, Université de Montpellier, Montpellier, France.,Laboratoire de Génétique Moléculaire, CHRU Montpellier, Montpellier, France
| | - Catherine Blanchet
- Service ORL, CHRU Montpellier, Montpellier, France.,CHU Montpellier, Centre National de Référence Maladies Rares, "Affections Sensorielles Génétiques, France
| | - Christian Hamel
- CHU Montpellier, Centre National de Référence Maladies Rares, "Affections Sensorielles Génétiques, France
| | - Sue Malcolm
- Genetics and Genomic Medicine Programme, Institute of Child Health, UCL, London, UK
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares EA 7402, Université de Montpellier, Montpellier, France.,Laboratoire de Génétique Moléculaire, CHRU Montpellier, Montpellier, France
| | - Mireille Claustres
- Laboratoire de Génétique de Maladies Rares EA 7402, Université de Montpellier, Montpellier, France.,Laboratoire de Génétique Moléculaire, CHRU Montpellier, Montpellier, France
| | - Anne-Françoise Roux
- Laboratoire de Génétique de Maladies Rares EA 7402, Université de Montpellier, Montpellier, France.,Laboratoire de Génétique Moléculaire, CHRU Montpellier, Montpellier, France
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12
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Functional Analysis of Mutations in Exon 9 of NF1 Reveals the Presence of Several Elements Regulating Splicing. PLoS One 2015; 10:e0141735. [PMID: 26509978 PMCID: PMC4624989 DOI: 10.1371/journal.pone.0141735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/11/2015] [Indexed: 11/19/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is one of the most common human hereditary disorders, predisposing individuals to the development of benign and malignant tumors in the nervous system, as well as other clinical manifestations. NF1 is caused by heterozygous mutations in the NF1 gene and around 25% of the pathogenic changes affect pre-mRNA splicing. Since the molecular mechanisms affected by these mutations are poorly understood, we have analyzed the splicing mutations identified in exon 9 of NF1, which is particularly prone to such changes, to better define the possible splicing regulatory elements. Using a minigene approach, we studied the effect of five splicing mutations in this exon described in patients. These highlighted three regulatory motifs within the exon. An in vivo splicing analysis of an extensive collection of changes generated in the minigene demonstrated that the CG motif at c.910-911 is critical for the recognition of exon 9. We also found that the GC motif at c.945-946 is involved in exon recognition through SRSF2 and that this motif is part of a Composite Exon Splicing Regulatory Element made up of physically overlapping enhancer and silencer elements. Finally, through an in vivo splicing analysis and in vitro binding assays, we demonstrated that the c.1007G>A mutation creates an Exonic Splicing Silencer element that binds the hnRNPA1 protein. The complexity of the splicing regulatory elements present in exon 9 is most likely responsible for the fact that mutations in this region represent 25% of all exonic changes that affect splicing in the NF1 gene.
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13
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Raynal C, Baux D, Theze C, Bareil C, Taulan M, Roux AF, Claustres M, Tuffery-Giraud S, des Georges M. A classification model relative to splicing for variants of unknown clinical significance: application to the CFTR gene. Hum Mutat 2013; 34:774-84. [PMID: 23381846 DOI: 10.1002/humu.22291] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 01/29/2013] [Indexed: 12/24/2022]
Abstract
Molecular diagnosis of cystic fibrosis and cystic fibrosis transmembrane regulator (CFTR)-related disorders led to the worldwide identification of nearly 1,900 sequence variations in the CFTR gene that consist mainly of private point mutations and small insertions/deletions. Establishing their effect on the function of the encoded protein and therefore their involvement in the disease is still challenging and directly impacts genetic counseling. In this context, we built a decision tree following the international guidelines for the classification of variants of unknown clinical significance (VUCS) in the CFTR gene specifically focused on their consequences on splicing. We applied general and specific criteria, including comprehensive review of literature and databases, familial genetics data, and thorough in silico studies. This model was tested on 15 intronic and exonic VUCS identified in our cohort. Six variants were classified as probably nonpathogenic considering their impact on splicing and eight as probably pathogenic, which include two apparent missense mutations. We assessed the validity of our method by performing minigenes studies and confirmed that 93% (14/15) were correctly classified. We provide in this study a high-performance method that can play a full role in interpreting the results of molecular diagnosis in emergency context, when functional studies are not achievable.
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Affiliation(s)
- Caroline Raynal
- CHU Montpellier, Hôpital Arnaud de Villeneuve, Laboratoire de Génétique Moléculaire, Montpellier, France.
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14
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Aparisi MJ, García-García G, Aller E, Sequedo MD, Martínez-Fernández de la Cámara C, Rodrigo R, Armengot M, Cortijo J, Milara J, Díaz-LLopis M, Jaijo T, Millán JM. Study of USH1 splicing variants through minigenes and transcript analysis from nasal epithelial cells. PLoS One 2013; 8:e57506. [PMID: 23451239 PMCID: PMC3581446 DOI: 10.1371/journal.pone.0057506] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 01/22/2013] [Indexed: 11/18/2022] Open
Abstract
Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by congenital profound deafness, vestibular areflexia and prepubertal retinitis pigmentosa. The first purpose of this study was to determine the pathologic nature of eighteen USH1 putative splicing variants found in our series and their effect in the splicing process by minigene assays. These variants were selected according to bioinformatic analysis. The second aim was to analyze the USH1 transcripts, obtained from nasal epithelial cells samples of our patients, in order to corroborate the observed effect of mutations by minigenes in patient’s tissues. The last objective was to evaluate the nasal ciliary beat frequency in patients with USH1 and compare it with control subjects. In silico analysis were performed using four bioinformatic programs: NNSplice, Human Splicing Finder, NetGene2 and Spliceview. Afterward, minigenes based on the pSPL3 vector were used to investigate the implication of selected changes in the mRNA processing. To observe the effect of mutations in the patient’s tissues, RNA was extracted from nasal epithelial cells and RT-PCR analyses were performed. Four MYO7A (c.470G>A, c.1342_1343delAG, c.5856G>A and c.3652G>A), three CDH23 (c.2289+1G>A, c.6049G>A and c.8722+1delG) and one PCDH15 (c.3717+2dupTT) variants were observed to affect the splicing process by minigene assays and/or transcripts analysis obtained from nasal cells. Based on our results, minigenes are a good approach to determine the implication of identified variants in the mRNA processing, and the analysis of RNA obtained from nasal epithelial cells is an alternative method to discriminate neutral Usher variants from those with a pathogenic effect on the splicing process. In addition, we could observe that the nasal ciliated epithelium of USH1 patients shows a lower ciliary beat frequency than control subjects.
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Affiliation(s)
- María José Aparisi
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
| | - Gema García-García
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
| | - Elena Aller
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
- Biomedical Network Research Center for Rare Diseases, Valencia, Spain
| | - María Dolores Sequedo
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
| | | | - Regina Rodrigo
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
| | - Miguel Armengot
- Rhinology Unit, General and University Hospital, Medical School, Valencia University, Valencia, Spain
| | - Julio Cortijo
- Research Foundation of the University General Hospital of Valencia, Valencia, Spain
- Biomedical Network Research Center for Respiratory Diseases, Valencia, Spain
- University of Valencia, Valencia, Spain
| | - Javier Milara
- Biomedical Network Research Center for Respiratory Diseases, Valencia, Spain
- Clinical Pharmacology Unit, University Clinic Hospital, Valencia, Spain
- Research Unit, University General Hospital Consortium, Valencia, Spain
| | - Manuel Díaz-LLopis
- Department of Ophthalmology, La Fe University Hospital, Medical School, Valencia University, Valencia, Spain
| | - Teresa Jaijo
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
- Biomedical Network Research Center for Rare Diseases, Valencia, Spain
- * E-mail:
| | - José María Millán
- Research Group on Sensorineural Diseases, Instituto de Investigación Sanitaria - La Fe, Valencia, Spain
- Biomedical Network Research Center for Rare Diseases, Valencia, Spain
- Genetics Unit, La Fe University Hospital, Valencia, Spain
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15
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García-García G, Besnard T, Baux D, Vaché C, Aller E, Malcolm S, Claustres M, Millan JM, Roux AF. The contribution of GPR98 and DFNB31 genes to a Spanish Usher syndrome type 2 cohort. Mol Vis 2013; 19:367-73. [PMID: 23441107 PMCID: PMC3580968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 02/11/2013] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Usher syndrome type 2 (USH2) is an autosomal recessive disease characterized by moderate to severe hearing loss and retinitis pigmentosa. To date, three disease-causing genes have been identified, USH2A, GPR98, and DFNB31, of which USH2A is clearly the major contributor. The aim of this work was to determine the contribution of GPR98 and DFNB31 genes in a Spanish cohort of USH2A negative patients using exhaustive molecular analysis, including sequencing, dosage, and splicing analysis. METHODS Linkage analysis was performed to prioritize the gene to study, followed by sequencing of exons and intron-exon boundaries of the selected gene, GPR98 (90 exons) or DFNB31 (12 exons). Functional splicing analyses and comparative genomic hybridization array to detect large rearrangements were performed when appropriate. RESULTS We confirmed that mutations in GPR98 contribute a significant but minor role to Usher syndrome type 2. In a group of patients referred for molecular diagnosis, 43 had been found to be positive for USH2A mutations, the remaining 19 without USH2A alterations were screened, and seven different mutations were identified in the GPR98 gene in seven patients (five in the homozygous state), of which six were novel. All detected mutations result in a truncated protein; deleterious missense mutations were not found. No pathological mutations were identified in the DFNB31 gene. CONCLUSIONS In Spain, USH2A and GPR98 are responsible for 95.8% and 5.2% of USH2 mutated cases, respectively. DFNB31 plays a minor role in the Spanish population. There was a group of patients in whom no mutation was found. These findings confirm the importance of including at least GPR98 analysis for comprehensive USH2 molecular diagnosis.
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Affiliation(s)
- Gema García-García
- INSERM, U827, Montpellier, F-34000, France,Grupo de Investigación en Enfermedades Neurosensoriales, Instituto de Investigación Sanitaria IIS-La Fe and Centro de Investigación Biomédica en Red de Enfermedades Raras, Valencia, Spain
| | - Thomas Besnard
- INSERM, U827, Montpellier, F-34000, France,Centre Hospitalier Universitaire, Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, F-34000, France,Université Montpellier 1, UFR de Médecine, Montpellier, France
| | - David Baux
- Centre Hospitalier Universitaire, Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, F-34000, France
| | - Christel Vaché
- Centre Hospitalier Universitaire, Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, F-34000, France
| | - Elena Aller
- Grupo de Investigación en Enfermedades Neurosensoriales, Instituto de Investigación Sanitaria IIS-La Fe and Centro de Investigación Biomédica en Red de Enfermedades Raras, Valencia, Spain
| | - Sue Malcolm
- Clinical and Molecular Genetics, Institute of Child Health, University College London, London, United Kingdom
| | - Mireille Claustres
- INSERM, U827, Montpellier, F-34000, France,Centre Hospitalier Universitaire, Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, F-34000, France,Université Montpellier 1, UFR de Médecine, Montpellier, France
| | - Jose M. Millan
- Grupo de Investigación en Enfermedades Neurosensoriales, Instituto de Investigación Sanitaria IIS-La Fe and Centro de Investigación Biomédica en Red de Enfermedades Raras, Valencia, Spain
| | - Anne-Françoise Roux
- INSERM, U827, Montpellier, F-34000, France,Centre Hospitalier Universitaire, Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, F-34000, France
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16
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Abstract
For most of our 25,000 genes, the removal of introns by pre-messenger RNA (pre-mRNA) splicing represents an essential step toward the production of functional messenger RNAs (mRNAs). Alternative splicing of a single pre-mRNA results in the production of different mRNAs. Although complex organisms use alternative splicing to expand protein function and phenotypic diversity, patterns of alternative splicing are often altered in cancer cells. Alternative splicing contributes to tumorigenesis by producing splice isoforms that can stimulate cell proliferation and cell migration or induce resistance to apoptosis and anticancer agents. Cancer-specific changes in splicing profiles can occur through mutations that are affecting splice sites and splicing control elements, and also by alterations in the expression of proteins that control splicing decisions. Recent progress in global approaches that interrogate splicing diversity should help to obtain specific splicing signatures for cancer types. The development of innovative approaches for annotating and reprogramming splicing events will more fully establish the essential contribution of alternative splicing to the biology of cancer and will hopefully provide novel targets and anticancer strategies. Metazoan genes are usually made up of several exons interrupted by introns. The introns are removed from the pre-mRNA by RNA splicing. In conjunction with other maturation steps, such as capping and polyadenylation, the spliced mRNA is then transported to the cytoplasm to be translated into a functional protein. The basic mechanism of splicing requires accurate recognition of each extremity of each intron by the spliceosome. Introns are identified by the binding of U1 snRNP to the 5' splice site and the U2AF65/U2AF35 complex to the 3' splice site. Following these interactions, other proteins and snRNPs are recruited to generate the complete spliceosomal complex needed to excise the intron. While many introns are constitutively removed by the spliceosome, other splice junctions are not used systematically, generating the phenomenon of alternative splicing. Alternative splicing is therefore the process by which a single species of pre-mRNA can be matured to produce different mRNA molecules (Fig. 1). Depending on the number and types of alternative splicing events, a pre-mRNA can generate from two to several thousands different mRNAs leading to the production of a corresponding number of proteins. It is now believed that the expression of at least 70 % of human genes is subjected to alternative splicing, implying an enormous contribution to proteomic diversity, and by extension, to the development and the evolution of complex animals. Defects in splicing have been associated with human diseases (Caceres and Kornblihtt, Trends Genet 18(4):186-93, 2002, Cartegni et al., Nat Rev Genet 3(4):285-98, 2002, Pagani and Baralle, Nat Rev Genet 5(5):389-96, 2004), including cancer (Brinkman, Clin Biochem 37(7):584-94, 2004, Venables, Bioessays 28(4):378-86, 2006, Srebrow and Kornblihtt, J Cell Sci 119(Pt 13):2635-2641, 2006, Revil et al., Bull Cancer 93(9):909-919, 2006, Venables, Transworld Res Network, 2006, Pajares et al., Lancet Oncol 8(4):349-57, 2007, Skotheim and Nees, Int J Biochem Cell Biol 39:1432-1449, 2007). Numerous studies have now confirmed the existence of specific differences in the alternative splicing profiles between normal and cancer tissues. Although there are a few cases where specific mutations are the primary cause for these changes, global alterations in alternative splicing in cancer cells may be primarily derived from changes in the expression of RNA-binding proteins that control splice site selection. Overall, these cancer-specific differences in alternative splicing offer an immense potential to improve the diagnosis and the prognosis of cancer. This review will focus on the functional impact of cancer-associated alternative splicing variants, the molecular determinants that alter the splicing decisions in cancer cells, and future therapeutic strategies.
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17
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Besnard T, Vaché C, Baux D, Larrieu L, Abadie C, Blanchet C, Odent S, Blanchet P, Calvas P, Hamel C, Dollfus H, Lina-Granade G, Lespinasse J, David A, Isidor B, Morin G, Malcolm S, Tuffery-Giraud S, Claustres M, Roux AF. Non-USH2A mutations in USH2 patients. Hum Mutat 2012; 33:504-10. [PMID: 22147658 DOI: 10.1002/humu.22004] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 11/28/2011] [Indexed: 11/08/2022]
Abstract
We have systematically analyzed the two known minor genes involved in Usher syndrome type 2, DFNB31 and GPR98, for mutations in a cohort of 31 patients not linked to USH2A. PDZD7, an Usher syndrome type 2 (USH2) related gene, was analyzed when indicated. We found that mutations in GPR98 contribute significantly to USH2. We report 17 mutations in 10 individuals, doubling the number of GPR98 mutations reported to date. In contrast to mutations in usherin, the mutational spectrum of GPR98 predominantly results in a truncated protein product. This is true even when the mutation affects splicing, and we have incorporated a splicing reporter minigene assay to show this, where appropriate. Only two mutations were found which we believe to be genuine missense changes. Discrepancy in the mutational spectrum between GPR98 and USH2A is discussed. Only two patients were found with mutations in DFNB31, showing that mutations of this gene contribute to only a very small extent to USH2. Close examination of the clinical details, where available, for patients in whom no mutation was found in USH2A, GPR98, or DFNB31, showed that most of them had atypical features. In effect, these three genes account for the vast majority of USH2 patients and their analysis provide a robust pathway for routine molecular diagnosis.
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Affiliation(s)
- Thomas Besnard
- CHU Montpellier, Laboratoire de Génétique Moléculaire, Montpellier, France
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Garcia-Garcia G, Aparisi MJ, Jaijo T, Rodrigo R, Leon AM, Avila-Fernandez A, Blanco-Kelly F, Bernal S, Navarro R, Diaz-Llopis M, Baiget M, Ayuso C, Millan JM, Aller E. Mutational screening of the USH2A gene in Spanish USH patients reveals 23 novel pathogenic mutations. Orphanet J Rare Dis 2011; 6:65. [PMID: 22004887 PMCID: PMC3207874 DOI: 10.1186/1750-1172-6-65] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 10/17/2011] [Indexed: 11/10/2022] Open
Abstract
Background Usher Syndrome type II (USH2) is an autosomal recessive disorder, characterized by moderate to severe hearing impairment and retinitis pigmentosa (RP). Among the three genes implicated, mutations in the USH2A gene account for 74-90% of the USH2 cases. Methods To identify the genetic cause of the disease and determine the frequency of USH2A mutations in a cohort of 88 unrelated USH Spanish patients, we carried out a mutation screening of the 72 coding exons of this gene by direct sequencing. Moreover, we performed functional minigene studies for those changes that were predicted to affect splicing. Results As a result, a total of 144 DNA sequence variants were identified. Based upon previous studies, allele frequencies, segregation analysis, bioinformatics' predictions and in vitro experiments, 37 variants (23 of them novel) were classified as pathogenic mutations. Conclusions This report provide a wide spectrum of USH2A mutations and clinical features, including atypical Usher syndrome phenotypes resembling Usher syndrome type I. Considering only the patients clearly diagnosed with Usher syndrome type II, and results obtained in this and previous studies, we can state that mutations in USH2A are responsible for 76.1% of USH2 disease in patients of Spanish origin.
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Affiliation(s)
- Gema Garcia-Garcia
- Grupo de Investigación en Enfermedades Neurosensoriales, Instituto de Investigación Sanitaria IIS-La Fe, Valencia, Spain
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Jaijo T, Aller E, Aparisi MJ, García-García G, Hernan I, Gamundi MJ, Nájera C, Carballo M, Millán JM. Functional analysis of splicing mutations in MYO7A and USH2A genes. Clin Genet 2011; 79:282-8. [DOI: 10.1111/j.1399-0004.2010.01454.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Le Guédard-Méreuze S, Vaché C, Baux D, Faugère V, Larrieu L, Abadie C, Janecke A, Claustres M, Roux AF, Tuffery-Giraud S. Ex vivo splicing assays of mutations at noncanonical positions of splice sites in USHER genes. Hum Mutat 2010; 31:347-55. [PMID: 20052763 DOI: 10.1002/humu.21193] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Molecular diagnosis in Usher syndrome type 1 and 2 patients led to the identification of 21 sequence variations located in noncanonical positions of splice sites in MYO7A, CDH23, USH1C, and USH2A genes. To establish experimentally the splicing pattern of these substitutions, whose impact on splicing is not always predictable by available softwares, ex vivo splicing assays were performed. The branch-point mapping strategy was also used to investigate further a putative branch-point mutation in USH2A intron 43. Aberrant splicing was demonstrated for 16 of the 21 (76.2%) tested sequence variations. The mutations resulted more frequently in activation of a nearby cryptic splice site or use of a de novo splice site than exon skipping (37.5%). This study allowed the reclassification as splicing mutations of one silent (c.7872G>A (p.Glu2624Glu) in CDH23) and four missense mutations (c.2993G>A (p.Arg998Lys) in USH2A, c.592G>A (p.Ala198Thr), c.3503G>C [p.Arg1168Pro], c.5944G>A (p.Gly1982Arg) in MYO7A), whereas it provided clues about a role in structure/function in four other cases: c.802G>A (p.Gly268Arg), c.653T>A (p.Val218Glu) (USH2A), and c.397C>T (p.His133Tyr), c.3502C>T (p.Arg1168Trp) (MYO7A). Our data provide insights into the contribution of splicing mutations in Usher genes and illustrate the need to define accurately their splicing outcome for diagnostic purposes.
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De Luca A, Sarkozy A, Ferese R, Consoli F, Lepri F, Dentici ML, Vergara P, De Zorzi A, Versacci P, Digilio MC, Marino B, Dallapiccola B. New mutations in ZFPM2/FOG2 gene in tetralogy of Fallot and double outlet right ventricle. Clin Genet 2010; 80:184-90. [PMID: 20807224 DOI: 10.1111/j.1399-0004.2010.01523.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Conotruncal defects (CTDs) represent 15-20% of all congenital heart defects. Mutations in a number of genes have been associated with CTD in humans and animal models. We investigated the occurrence and the prevalence of GATA4, NKX2.5, ZFPM2/FOG2, GDF1, and ISLET1 gene mutations in a large cohort of individuals with CTD, including tetralogy of Fallot with or without pulmonary atresia (TOF, 178 patients), double outlet right ventricle (DORV, 13 patients), and truncus arteriosus (11 patients). Denaturing high-performance liquid chromatography (DHPLC) analysis followed by bidirectional sequencing disclosed no putative pathogenic mutation in GATA4, ISLET1, and GDF1 genes. Two novel (Ile227Val, Met544Ile) and one previously reported (Glu30Gly) possibly pathogenic missense variants were identified in the ZFPM2/FOG2 gene in 3 sporadic patients of 202 (1.5%) with CTD, including 1 of 178 (0.6%) with TOF and 2 of 13 (15.4%) with DORV. Mutation analysis also detected one known missense change (Arg25Cys) in NKX2.5 gene in two (1.1%) sporadic patients with TOF. These sequence alterations were found to be absent in 500 population-matched controls. In conclusion, the present results (i) indicate and confirm that mutations in the GATA4, GDF1, and ISLET1 genes are not major determinants in the pathogenesis of TOF, (ii) provide supportive evidence of an association between ZFPM2/FOG2 gene and TOF/DORV, and (iii) provide additional examples of the possible contribution of the Arg25Cys change in the NKX2.5 to a small number of TOF cases.
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Affiliation(s)
- Alessandro De Luca
- CSS-Mendel Institute, Casa Sollievo della Sofferenza Hospital, IRCCS, San Giovanni Rotondo, Rome, Italy.
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Kaleem A, Ahmad I, Walker-Nasir E, Hoessli DC, Shakoori AR. Effect on the Ras/Raf signaling pathway of post-translational modifications of neurofibromin: in silico study of protein modification responsible for regulatory pathways. J Cell Biochem 2010; 108:816-24. [PMID: 19718661 DOI: 10.1002/jcb.22301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mapping and chemical characterization of post-translational modifications (PTMs) in proteins are critical to understand the regulatory mechanisms involving modified proteins and their role in disease. Neurofibromatosis type 1 (NF-1) is an autosomal dominantly inherited disorder, where NF1 mutations usually result in a reduced level of the tumor suppressor protein, neurofibromin (NF). NF is a multifunctional cytoplasmic protein that regulates microtubule dynamics and participates in several signaling pathways, particularly the RAS signaling pathway. NF is a Ras GTPase-activating protein (GAP) that prevents oncogenesis by converting GTP-Ras to GDP-Ras. This function of NF is regulated by phosphorylation. Interplay of phosphorylation with O-GlcNAc modification on the same or vicinal Ser/Thr residues, the Yin Yang sites, is well known in cytoplasmic and nuclear proteins. The dynamic aspects of PTMs and their interplay being difficult to follow in vivo, we undertook this in silico work to predict and define the possible role of Yin Yang sites in NF-1. Interplay of phosphorylation and O-GlcNAc modification is proposed as a mechanism controlling the Ras signaling pathway.
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Affiliation(s)
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- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan.
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Coassin S, Brandstätter A, Kronenberg F. Lost in the space of bioinformatic tools: a constantly updated survival guide for genetic epidemiology. The GenEpi Toolbox. Atherosclerosis 2009; 209:321-35. [PMID: 19963217 DOI: 10.1016/j.atherosclerosis.2009.10.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 10/08/2009] [Accepted: 10/14/2009] [Indexed: 12/13/2022]
Abstract
Genome-wide association studies (GWASs) led to impressive advances in the elucidation of genetic factors underlying complex phenotypes and diseases. However, the ability of GWAS to identify new susceptibility loci in a hypothesis-free approach requires tools to quickly retrieve comprehensive information about a genomic region and analyze the potential effects of coding and non-coding SNPs in a candidate gene region. Furthermore, once a candidate region is chosen for resequencing and fine-mapping studies, the identification of several rare mutations is likely and requires strong bioinformatic support to properly evaluate and prioritize the found mutations for further analysis. Due to the variety of regulatory layers that can be affected by a mutation, a comprehensive in-silico evaluation of candidate SNPs can be a demanding and very time-consuming task. Although many bioinformatic tools that significantly simplify this task were made available in the last years, their utility is often still unknown to researches not intensively involved in bioinformatics. We present a comprehensive guide of 64 tools and databases to bioinformatically analyze gene regions of interest to predict SNP effects. In addition, we discuss tools to perform data mining of large genetic regions, predict the presence of regulatory elements, make in-silico evaluations of SNPs effects and address issues ranging from interactome analysis to graphically annotated proteins sequences. Finally, we exemplify the use of these tools by applying them to hits of a recently performed GWAS. Taken together a combination of the discussed tools are summarized and constantly updated in the web-based "GenEpi Toolbox" (http://genepi_toolbox.i-med.ac.at) and can help to get a glimpse at the potential functional relevance of both large genetic regions and single nucleotide mutations which might help to prioritize the next steps.
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Affiliation(s)
- Stefan Coassin
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Schöpfstr. 41, A-6020 Innsbruck, Austria
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Vidal C, Cachia A, Xuereb-Anastasi A. Effects of a synonymous variant in exon 9 of the CD44 gene on pre-mRNA splicing in a family with osteoporosis. Bone 2009; 45:736-42. [PMID: 19580891 DOI: 10.1016/j.bone.2009.06.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 06/23/2009] [Accepted: 06/25/2009] [Indexed: 10/20/2022]
Abstract
In a previous linkage study, suggestive linkage to osteoporosis was observed in marker D11S1392 on chromosome 11p12. The CD44 gene, found at this locus, was sequenced in one of the families studied. Sequencing all coding regions and promoter in affected and non-affected family members revealed a number of sequence variants, one of which was found to be linked and inherited identical by descent together with the linked STR allele. This G to A variant, which does not cause an amino acid change, was found in exon 9 of the CD44 gene, 32 base pairs upstream from the exon-intron junction. Preliminary analysis using a bioinformatics tool suggested that the presence of the A allele abolished an exon splicing enhancer (ESE) site, thus possibly affecting RNA splicing. It was observed using an exon-trapping vector, that in the presence of the A allele, only one transcript was observed in RAW264.7 cells, as opposed to two transcripts transcribed in the presence of the G allele. These observations suggest that the linked synonymous variant found in exon 9 of the CD44 gene might be increasing susceptibility to osteoporosis in this family by affecting the splicing mechanism.
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Affiliation(s)
- Christopher Vidal
- Department of Pathology, University of Malta, Medical School, G'Mangia, Malta
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Vidal C, Borg J, Xuereb-Anastasi A, Scerri CA. Variants within protectin (CD59) and CD44 genes linked to an inherited haplotype in a family with coeliac disease. TISSUE ANTIGENS 2009; 73:225-235. [PMID: 19254252 DOI: 10.1111/j.1399-0039.2008.01193.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Coeliac disease (CD) is an autoimmune disorder characterised by inflammation, villous atrophy and hyperplasia of the small intestinal mucosa that affects genetically susceptible individuals. A genome-wide scan was performed in 17 family members with high incidence of CD. Highest nonparametric linkage (NPL) and logarithm of odds (LOD) scores were of 6.21 (P = 0.0107) and 2.57, respectively, to a region on chromosome 11p13-12. Following fine mapping, NPL and LOD scores did not change, but the linkage interval on chromosome 11 was narrowed to a region that is approximately 50.94 cM from pTer. Two inherited haplotypes on chromosomes 11p13-12 and 9q21 were observed in all affected members but not in the majority of clinically normal individuals. Sequencing of genes at region 11p13-12 showed a number of sequence variants, two of which were linked with the inherited haplotype. One of these variants in the CD59 gene was found at a very low frequency in the population and could possibly affect pre-messenger RNA splicing. This study is of particular importance for the identification of novel genes that might be responsible for CD other than human leukocyte antigen.
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Affiliation(s)
- C Vidal
- Laboratory of Molecular Genetics, Department of Physiology and Biochemistry, University of Malta, Msida, Malta
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