1. Molecular Genetic Analysis of the PLP1 Gene in 38 Families with PLP1-related disorders: Identification and Functional Characterization of 11 Novel PLP1 Mutations
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David Neil Cooper, Ercan Demir, Andrea Rossi, Fabio Corsolini, Serena Grossi, Valentina Marchiani, Roberta Biancheri, Susanna Lualdi, Alessandro Simonati, Mirella Filocamo, Antonio Percesepe, Matthew Mort, Graziella Uziel, Catherine Vaurs-Barrière, Enrico Bertini, Franco Stanzial, Odile Boespflug-Tanguy, Stefano Regis, S.S.D. Lab. Diagnosi Pre-Postnatale Malattie Metaboliche, IRCCS G. Gaslini, U.O. Neuropsichiatria Infantile, Institute of Medical Genetics, Cardiff University-School of Medicine, Laboratory of Molecular Medicine, IRCCS Ospedale Pediatrico Bambino Gesù [Roma], Child Neurology Department, Fondazione IRCCS Istituto Neurologico, Génétique, Reproduction et Développement (GReD), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Centre de référence des leucodystrophies, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Service de neurologie pédiatrique et maladies métaboliques, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Robert Debré-Université Paris Diderot - Paris 7 (UPD7), Department of Neurological Neuropsychological, Morphological and Motor Sciences Section, Neurology-Child Neurology and Psychiatry Unit, Department of Child Neurology, Gazi University, U.O. Neuropsichiatria Infantile Azienda, Ospedaliera S.Orsola-Malpighi, Unit of Medical Genetics, Università degli Studi di Modena e Reggio Emilia = University of Modena and Reggio Emilia (UNIMORE)-Dept. of Mother and Child, Servizio di Consulenza Genetica, Centro Provinciale di Coordinamento della Rete delle Malattie Rare, Servizio di Neuroradiologia Pediatrica, The patient samples were obtained from the 'Cell Line and DNA Biobank from Patients Affected by Genetic Diseases' (G. Gaslini Institute) - Telethon Genetic Biobank Network (Project No. GTB07001A). This work was partially supported by grants from FP7-HEALTH - LeukoTreat no.241622, European Project: 241622,EC:FP7:HEALTH,FP7-HEALTH-2009-single-stage,LEUKOTREAT(2010), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut National de la Santé et de la Recherche Médicale (INSERM), Università degli Studi di Modena e Reggio Emilia (UNIMORE)-Dept. of Mother and Child, BMC, Ed., and Therapeutic challenge in Leukodystrophies: Translational and ethical research towards clinical trials - LEUKOTREAT - - EC:FP7:HEALTH2010-03-01 - 2013-08-31 - 241622 - VALID
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Male ,spastic paraplegia type 2 ,plp1 gene ,Adolescent ,lcsh:Medicine ,PLP1 mutations ,[SDV.GEN] Life Sciences [q-bio]/Genetics ,Biology ,PLP1 Gene ,medicine.disease_cause ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,PLP1-related disorders ,Gene Duplication ,Gene duplication ,medicine ,Humans ,Missense mutation ,Pelizaeus-Merzbacher disease ,Genetics(clinical) ,Pharmacology (medical) ,Child ,Myelin Proteolipid Protein ,Gene ,mutation analysis ,Genetics (clinical) ,030304 developmental biology ,Genetics ,Medicine(all) ,0303 health sciences ,Mutation ,[SDV.GEN]Life Sciences [q-bio]/Genetics ,Spastic Paraplegia, Hereditary ,Research ,lcsh:R ,Infant ,DNA ,General Medicine ,Exon skipping ,nervous system diseases ,3. Good health ,Child, Preschool ,RNA splicing ,Allelic heterogeneity ,030217 neurology & neurosurgery ,Minigene - Abstract
Background The breadth of the clinical spectrum underlying Pelizaeus-Merzbacher disease and spastic paraplegia type 2 is due to the extensive allelic heterogeneity in the X-linked PLP1 gene encoding myelin proteolipid protein (PLP). PLP1 mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients. Methods Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for PLP1 gene duplications using real-time PCR. PLP1 gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial PLP1 gene mutation was determined as well as 15/24 potential carrier mothers of the PLP1 duplication. Results and Conclusions PLP1 gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic PLP1 mutations were found in the remaining 14 patients. Of the 14 different intragenic lesions, 11 were novel; these included one nonsense and 7 missense mutations, a 657-bp deletion, a microdeletion and a microduplication. The functional significance of the novel PLP1 missense mutations, all occurring at evolutionarily conserved residues, was analysed by the MutPred tool whereas their potential effect on splicing was ascertained using the Skippy algorithm and a neural network. Although MutPred predicted that all 7 novel missense mutations would be likely to be deleterious, in silico analysis indicated that four of them (p.Leu146Val, p.Leu159Pro, p.Thr230Ile, p.Ala247Asp) might cause exon skipping by altering exonic splicing elements. These predictions were then investigated in vitro for both p.Leu146Val and p.Thr230Ile by means of RNA or minigene studies and were subsequently confirmed in the case of p.Leu146Val. Peripheral neuropathy was noted in four patients harbouring intragenic mutations that altered RNA processing, but was absent from all PLP1-duplication patients. Unprecedentedly, family studies revealed the de novo occurrence of the PLP1 duplication at a frequency of 20%.
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- 2011