Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal

Spinal Muscular Atrophy (SMA) is one of the most common autosomal recessive illnesses, caused by mutations of the SMN1 gene. SMA is characterized by symmetric proximal muscle weakness secondary to degeneration of the anterior horn cells of the spinal cord. SMA is clinically subdivided into four type...

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Autor principal: Medrano, María Sofía
Otros Autores: Monges, María Soledad
Formato: Tesis de maestría acceptedVersion
Lenguaje:Español
Publicado: Facultad de Farmacia y Bioquímica 2013
Materias:
Gen SMN2
Gen NAIP
Atrofia muscular espinal
AME
Ciencia de la vida
Acceso en línea:http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=afamaster&cl=CL1&d=HWA_811
http://repositoriouba.sisbi.uba.ar/gsdl/collect/afamaster/index/assoc/HWA_811.dir/811.PDF
Aporte de:
Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires
id I28-R145-HWA_811
record_format dspace
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-145
collection Repositorio Digital de la Universidad de Buenos Aires (UBA)
language Español
orig_language_str_mv spa
topic Gen SMN2
Gen NAIP
Atrofia muscular espinal
AME
Ciencia de la vida
spellingShingle Gen SMN2
Gen NAIP
Atrofia muscular espinal
AME
Ciencia de la vida
Medrano, María Sofía
Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal
topic_facet Gen SMN2
Gen NAIP
Atrofia muscular espinal
AME
Ciencia de la vida
description Spinal Muscular Atrophy (SMA) is one of the most common autosomal recessive illnesses, caused by mutations of the SMN1 gene. SMA is characterized by symmetric proximal muscle weakness secondary to degeneration of the anterior horn cells of the spinal cord. SMA is clinically subdivided into four types, ranging from the severe neonatal presentation to the adult form with minimum weakness. Phenotypic variability has been associated with the number of copies of SMN2, a gene that is highly homologous and close to SMN1. Unlike SMN1, the SMN2 gene produces only 10%-15% of functional protein. Currently several clinic research studies are being developed with drugs that stimulate increased synthesis of functional SMN protein from SMN2, including valproic acid (VPA) and 4-phenylbutyrate. Another gene close to SMN1, called NAIP, is deleted in most patients with severe SMA.\nObjectives\nThe main objective of this work was to evaluate the influence of the SMN2 copy number and absence of NAIP gene in SMA phenotype in children diagnosed at the Pediatric Hospital J.P Garrahan. For this purpose:\n- SMN2 copy number was determined through two semiquantitative molecular biology methodologies.\n- Presence or absence of NAIP gene was established.\n- A genotype-phenotype correlation study was conducted in SMA children of our population.\nPatients and Methodology\nWe studied 144 children diagnosed with SMA; these were categorized according to the criteria established by the ?Consensus Statement for Standard of Care in Spinal Muscular Atrophy, 2007?. The number of copies of the SMN2 gene was determined by MLPA (Multiplex Ligation-dependet Probe Amplification) and Real Time PCR. The absence of NAIP gene was established by MLPA.\nResults\nThe SMN2 copy number could be determined in all patients by MLPA. With the real time PCR it could be established in 119/144 patients. The results obtained by both techniques were equivalent in 95% of cases.\nAll children with SMA type I had 2 copies of SMN2, while over 98% of patients with SMA type II and II showed between 3 and 4 SMN2 copies. Only in the group of patients with SMA type III were observed 4 copies of SMN2, being these more frequent in patients with the subtype IIIb.\nThe NAIP gene was absent in 73,2% of children with SMA type I and present in more than 85% of patients with SMA type II and III.\nConclusions\nThe MLPA methodology proved to be more robust than real-time PCR and provides more information about SMA region.\nThe number of copies of SMN2 and the absence of NAIP gene showed to be phenotypic modifiers of SMA in the study population. These biomarkers do not explain all cases, suggesting the existence of other modifying factors that are still unknown and should be disclosed in future research.\nThis project contributed to the incorporation of a new methodology that increases diagnostic sensitivity (exceeding 95%) and allows detection of carriers in the family group.
author2 Monges, María Soledad
author_facet Monges, María Soledad
Medrano, María Sofía
format Tesis de maestría
Tesis de maestría
acceptedVersion
author Medrano, María Sofía
author_sort Medrano, María Sofía
title Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal
title_short Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal
title_full Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal
title_fullStr Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal
title_full_unstemmed Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal
title_sort influencia del número de copias del gen smn2 y de la deleción del gen naip en el fenotipo de la atrofia muscular espinal
publisher Facultad de Farmacia y Bioquímica
publishDate 2013
url http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=afamaster&cl=CL1&d=HWA_811
http://repositoriouba.sisbi.uba.ar/gsdl/collect/afamaster/index/assoc/HWA_811.dir/811.PDF
work_keys_str_mv AT medranomariasofia influenciadelnumerodecopiasdelgensmn2ydeladeleciondelgennaipenelfenotipodelaatrofiamuscularespinal
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spelling I28-R145-HWA_8112019-09-27 Spinal Muscular Atrophy (SMA) is one of the most common autosomal recessive illnesses, caused by mutations of the SMN1 gene. SMA is characterized by symmetric proximal muscle weakness secondary to degeneration of the anterior horn cells of the spinal cord. SMA is clinically subdivided into four types, ranging from the severe neonatal presentation to the adult form with minimum weakness. Phenotypic variability has been associated with the number of copies of SMN2, a gene that is highly homologous and close to SMN1. Unlike SMN1, the SMN2 gene produces only 10%-15% of functional protein. Currently several clinic research studies are being developed with drugs that stimulate increased synthesis of functional SMN protein from SMN2, including valproic acid (VPA) and 4-phenylbutyrate. Another gene close to SMN1, called NAIP, is deleted in most patients with severe SMA.\nObjectives\nThe main objective of this work was to evaluate the influence of the SMN2 copy number and absence of NAIP gene in SMA phenotype in children diagnosed at the Pediatric Hospital J.P Garrahan. For this purpose:\n- SMN2 copy number was determined through two semiquantitative molecular biology methodologies.\n- Presence or absence of NAIP gene was established.\n- A genotype-phenotype correlation study was conducted in SMA children of our population.\nPatients and Methodology\nWe studied 144 children diagnosed with SMA; these were categorized according to the criteria established by the ?Consensus Statement for Standard of Care in Spinal Muscular Atrophy, 2007?. The number of copies of the SMN2 gene was determined by MLPA (Multiplex Ligation-dependet Probe Amplification) and Real Time PCR. The absence of NAIP gene was established by MLPA.\nResults\nThe SMN2 copy number could be determined in all patients by MLPA. With the real time PCR it could be established in 119/144 patients. The results obtained by both techniques were equivalent in 95% of cases.\nAll children with SMA type I had 2 copies of SMN2, while over 98% of patients with SMA type II and II showed between 3 and 4 SMN2 copies. Only in the group of patients with SMA type III were observed 4 copies of SMN2, being these more frequent in patients with the subtype IIIb.\nThe NAIP gene was absent in 73,2% of children with SMA type I and present in more than 85% of patients with SMA type II and III.\nConclusions\nThe MLPA methodology proved to be more robust than real-time PCR and provides more information about SMA region.\nThe number of copies of SMN2 and the absence of NAIP gene showed to be phenotypic modifiers of SMA in the study population. These biomarkers do not explain all cases, suggesting the existence of other modifying factors that are still unknown and should be disclosed in future research.\nThis project contributed to the incorporation of a new methodology that increases diagnostic sensitivity (exceeding 95%) and allows detection of carriers in the family group. Fil: Medrano, María Sofía. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Monges, María Soledad Facultad de Farmacia y Bioquímica Chertkoff, Lilien Medrano, María Sofía 2013-12-16 La Atrofia Muscular Espinal (AME) es una de las enfermedades autosómicas recesivas más frecuentes, y es causada por mutaciones en el gen SMN1. Esta enfermedad neuromuscular se caracteriza por degeneración de las motoneuronas del asta anterior de la medula espinal resultando en atrofia y debilidad muscular progresiva. Existen 4 formas clínicas de presentación desde la manifestación neonatal severa a la forma del adulto con mínima debilidad. La severidad de la enfermedad se ha correlacionado con el número de copias del gen SMN2, altamente homólogo y cercano a SMN1. El gen SMN2, a diferencia de SMN1, produce sólo un 10%-15% de proteína SMN activa. Actualmente se están desarrollando estudios de investigación clínicos con medicamentos que estimulan una mayor síntesis de proteína activa a partir de SMN2, entre ellos ácido valproico (VPA) y 4-fenilbutirato. Otro gen cercano a SMN1, denominado NAIP, se encuentra delecionado en la mayoría de los pacientes con AME severa.\nObjetivos\nEl objetivo principal de este trabajo fue evaluar la influencia del número de copias del gen SMN2 y la ausencia del gen NAIP, en el fenotipo AME en niños diagnosticados en el Hospital de Pediatría J. P. Garrahan. Para ello:\n- Se determinó el número de copias del gen SMN2 mediante dos metodologías semicuantitativas de biología molecular\n- Se estableció la presencia o ausencia del gen NAIP\n- Se realizó un estudio de correlación Genotipo-Fenotipo en los niños con AME de nuestra población\nPacientes y Métodos\nSe estudiaron 144 niños con diagnóstico de AME; los mismos fueron categorizados de\nacuerdo a los criterios establecidos por el Consenso Internacional de AME ?Consensus\nStatement for Standard of Care in Spinal Muscular Atrophy, 2007?. El número de copias del gen SMN2 se determinó mediante MLPA (Multiplex Ligation-dependet Probe Amplification) y PCR a tiempo real. La ausencia del gen NAIP se determinó mediante la metodología de MLPA.\nResultados\nEl número de copias del gen SMN2 pudo ser determinado mediante MLPA en la\ntotalidad de los pacientes. Con la PCR a tiempo real se pudo establecer en 119/144\npacientes. Los resultados obtenidos por ambas técnicas fueron equivalentes en el 95%\nde los casos.\nTodos los niños con AME tipo I presentaron 2 copias, mientras que más del 98% de los\npacientes con AME tipo II y III mostraron entre 3 y 4 copias de SMN2. Sólo en el grupo\nAME tipo III se observaron 4 copias de SMN2, siendo éstas más frecuente en los\npacientes con el subtipo IIIb.\nEl gen NAIP estuvo ausente en el 73,2% de los niños con AME tipo I y presente en más\ndel 85% de los pacientes con AME tipo II y III.\nConclusiones\nLa metodología de MLPA resultó ser más robusta que la PCR a tiempo real y brinda\nmayor información acerca de la región AME.\nEl número de copias del gen SMN2 y la ausencia del gen NAIP mostraron ser modificadores del fenotipo clínico de AME en la población estudiada. Estos biomarcadores no alcanzan a explicar la totalidad de los casos, sugiriendo la existencia\nde otros factores modificadores que aún no se conocen y deberán ser revelados en futuras investigaciones.\nEl presente proyecto contribuyó a la incorporación de una nueva metodología que aumenta la sensibilidad diagnóstica (superando el 95%) y que permite la detección de portadores en el grupo familiar. application/pdf Perandones, Claudia Dain, Liliana Caputo, Mariela Gen SMN2 Gen NAIP Atrofia muscular espinal AME spa Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/2.5/ar/ Ciencia de la vida Influencia del número de copias del gen SMN2 y de la deleción del gen NAIP en el fenotipo de la Atrofia Muscular Espinal info:eu-repo/semantics/masterThesis info:ar-repo/semantics/tesis de maestría info:eu-repo/semantics/acceptedVersion http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=afamaster&cl=CL1&d=HWA_811 http://repositoriouba.sisbi.uba.ar/gsdl/collect/afamaster/index/assoc/HWA_811.dir/811.PDF

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