Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations

<p>Abstract</p> <p>Background</p> <p>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 <it>PLP1 </it>gene encoding myelin proteolipid prote...

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Main Authors: Marchiani Valentina, Demir Ercan, Corsolini Fabio, Simonati Alessandro, Boespflug-Tanguy Odile, Uziel Graziella, Bertini Enrico, Lualdi Susanna, Mort Matthew, Biancheri Roberta, Regis Stefano, Grossi Serena, Percesepe Antonio, Stanzial Franco, Rossi Andrea, Vaurs-Barrière Catherine, Cooper David N, Filocamo Mirella
Format: Article
Language:English
Published: BMC 2011-06-01
Series:Orphanet Journal of Rare Diseases
Online Access:http://www.ojrd.com/content/6/1/40
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author Marchiani Valentina
Demir Ercan
Corsolini Fabio
Simonati Alessandro
Boespflug-Tanguy Odile
Uziel Graziella
Bertini Enrico
Lualdi Susanna
Mort Matthew
Biancheri Roberta
Regis Stefano
Grossi Serena
Percesepe Antonio
Stanzial Franco
Rossi Andrea
Vaurs-Barrière Catherine
Cooper David N
Filocamo Mirella
author_facet Marchiani Valentina
Demir Ercan
Corsolini Fabio
Simonati Alessandro
Boespflug-Tanguy Odile
Uziel Graziella
Bertini Enrico
Lualdi Susanna
Mort Matthew
Biancheri Roberta
Regis Stefano
Grossi Serena
Percesepe Antonio
Stanzial Franco
Rossi Andrea
Vaurs-Barrière Catherine
Cooper David N
Filocamo Mirella
author_sort Marchiani Valentina
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>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 <it>PLP1 </it>gene encoding myelin proteolipid protein (PLP). <it>PLP1 </it>mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients.</p> <p>Methods</p> <p>Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for <it>PLP1 </it>gene duplications using real-time PCR. <it>PLP1 </it>gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial <it>PLP1 </it>gene mutation was determined as well as 15/24 potential carrier mothers of the <it>PLP1 </it>duplication.</p> <p>Results and Conclusions</p> <p><it>PLP1 </it>gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic <it>PLP1 </it>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 <it>PLP1 </it>missense mutations, all occurring at evolutionarily conserved residues, was analysed by the <it>MutPred </it>tool whereas their potential effect on splicing was ascertained using the <it>Skippy </it>algorithm and a neural network. Although <it>MutPred </it>predicted that all 7 novel missense mutations would be likely to be deleterious, <it>in silico </it>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 <it>in vitro </it>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 <it>PLP1</it>-duplication patients. Unprecedentedly, family studies revealed the <it>de novo </it>occurrence of the <it>PLP1 </it>duplication at a frequency of 20%.</p>
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spelling doaj.art-113765785a024c339af3c1f7ef99b6392022-12-22T01:02:46ZengBMCOrphanet Journal of Rare Diseases1750-11722011-06-01614010.1186/1750-1172-6-40Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>MutationsMarchiani ValentinaDemir ErcanCorsolini FabioSimonati AlessandroBoespflug-Tanguy OdileUziel GraziellaBertini EnricoLualdi SusannaMort MatthewBiancheri RobertaRegis StefanoGrossi SerenaPercesepe AntonioStanzial FrancoRossi AndreaVaurs-Barrière CatherineCooper David NFilocamo Mirella<p>Abstract</p> <p>Background</p> <p>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 <it>PLP1 </it>gene encoding myelin proteolipid protein (PLP). <it>PLP1 </it>mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients.</p> <p>Methods</p> <p>Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for <it>PLP1 </it>gene duplications using real-time PCR. <it>PLP1 </it>gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial <it>PLP1 </it>gene mutation was determined as well as 15/24 potential carrier mothers of the <it>PLP1 </it>duplication.</p> <p>Results and Conclusions</p> <p><it>PLP1 </it>gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic <it>PLP1 </it>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 <it>PLP1 </it>missense mutations, all occurring at evolutionarily conserved residues, was analysed by the <it>MutPred </it>tool whereas their potential effect on splicing was ascertained using the <it>Skippy </it>algorithm and a neural network. Although <it>MutPred </it>predicted that all 7 novel missense mutations would be likely to be deleterious, <it>in silico </it>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 <it>in vitro </it>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 <it>PLP1</it>-duplication patients. Unprecedentedly, family studies revealed the <it>de novo </it>occurrence of the <it>PLP1 </it>duplication at a frequency of 20%.</p>http://www.ojrd.com/content/6/1/40
spellingShingle Marchiani Valentina
Demir Ercan
Corsolini Fabio
Simonati Alessandro
Boespflug-Tanguy Odile
Uziel Graziella
Bertini Enrico
Lualdi Susanna
Mort Matthew
Biancheri Roberta
Regis Stefano
Grossi Serena
Percesepe Antonio
Stanzial Franco
Rossi Andrea
Vaurs-Barrière Catherine
Cooper David N
Filocamo Mirella
Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations
Orphanet Journal of Rare Diseases
title Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations
title_full Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations
title_fullStr Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations
title_full_unstemmed Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations
title_short Molecular Genetic Analysis of the <it>PLP1 </it>Gene in 38 Families with <it>PLP1</it>-related disorders: Identification and Functional Characterization of 11 Novel <it>PLP1 </it>Mutations
title_sort molecular genetic analysis of the it plp1 it gene in 38 families with it plp1 it related disorders identification and functional characterization of 11 novel it plp1 it mutations
url http://www.ojrd.com/content/6/1/40
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