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Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas

BACKGROUND: Multiple osteochondromas is a dysplasia characterized by growth of two or more osteochondromas. It is genetically heterogeneous, caused by pathogenic variants in EXT1 or EXT2 genes in 70%–90% of patients. The EXT1 is more often mutated than EXT2 gene, with a variable prevalence between p...

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Autores principales: Santos, Savana C. L., Rizzo, Isabela M. P. O., Takata, Reinaldo I., Speck‐Martins, Carlos E., Brum, Jaime M., Sollaci, Claudio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014457/
https://www.ncbi.nlm.nih.gov/pubmed/29529714
http://dx.doi.org/10.1002/mgg3.382
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author Santos, Savana C. L.
Rizzo, Isabela M. P. O.
Takata, Reinaldo I.
Speck‐Martins, Carlos E.
Brum, Jaime M.
Sollaci, Claudio
author_facet Santos, Savana C. L.
Rizzo, Isabela M. P. O.
Takata, Reinaldo I.
Speck‐Martins, Carlos E.
Brum, Jaime M.
Sollaci, Claudio
author_sort Santos, Savana C. L.
collection PubMed
description BACKGROUND: Multiple osteochondromas is a dysplasia characterized by growth of two or more osteochondromas. It is genetically heterogeneous, caused by pathogenic variants in EXT1 or EXT2 genes in 70%–90% of patients. The EXT1 is more often mutated than EXT2 gene, with a variable prevalence between populations. There are no data about EXT1 and EXT2 pathogenic variants in patients with multiple osteochondromas in Brazilian population. The aim of this survey is to characterize these to determine the genotype profile of this population. METHODS: DNA sequencing (Sanger Method) and MLPA analysis were performed to identify point mutations and deletions/duplications in the sample of 153 patients in 114 families. RESULTS: Germline variants were identified in 83% of families in which EXT2 variants were detected in 46% and EXT1 in 37% of cases. No variants were detected in 17% of them. We identified 50 different variants, 33 (13 frameshift, 11 nonsense, 5 missense, 2 splice site mutation, and 2 large deletions) in EXT1 and 17 (6 frameshift, 6 splice site mutation, 3 nonsense, 1 missense, and 1 large deletion) in EXT2. Of all 50 variants, 31 (62%) were novel, including 20 out of 33 (60,6%) EXT1 and 11 out of 17 (64.7%) EXT2 alleles. The vast majority of variants (88%) were “loss‐of‐function” and two novel hotspots in EXT2 gene were observed in our study. CONCLUSION: The prevalence of variants detected in the EXT2 gene differs from other researches from Latin America, European, and Asian population. This uncommon prevalence could be related with the newly characterized variant hotspot sites detected in EXT2 gene (p.Ala409Profs*26 and p.Ser290*). A high number of novel variants were also identified indicating that Brazilian population has a unique genetic profile. Characterizing this population and establishing its genotype is essential to understand the molecular pathogenesis of this disease in Brazil.
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spelling pubmed-60144572018-07-05 Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas Santos, Savana C. L. Rizzo, Isabela M. P. O. Takata, Reinaldo I. Speck‐Martins, Carlos E. Brum, Jaime M. Sollaci, Claudio Mol Genet Genomic Med Original Articles BACKGROUND: Multiple osteochondromas is a dysplasia characterized by growth of two or more osteochondromas. It is genetically heterogeneous, caused by pathogenic variants in EXT1 or EXT2 genes in 70%–90% of patients. The EXT1 is more often mutated than EXT2 gene, with a variable prevalence between populations. There are no data about EXT1 and EXT2 pathogenic variants in patients with multiple osteochondromas in Brazilian population. The aim of this survey is to characterize these to determine the genotype profile of this population. METHODS: DNA sequencing (Sanger Method) and MLPA analysis were performed to identify point mutations and deletions/duplications in the sample of 153 patients in 114 families. RESULTS: Germline variants were identified in 83% of families in which EXT2 variants were detected in 46% and EXT1 in 37% of cases. No variants were detected in 17% of them. We identified 50 different variants, 33 (13 frameshift, 11 nonsense, 5 missense, 2 splice site mutation, and 2 large deletions) in EXT1 and 17 (6 frameshift, 6 splice site mutation, 3 nonsense, 1 missense, and 1 large deletion) in EXT2. Of all 50 variants, 31 (62%) were novel, including 20 out of 33 (60,6%) EXT1 and 11 out of 17 (64.7%) EXT2 alleles. The vast majority of variants (88%) were “loss‐of‐function” and two novel hotspots in EXT2 gene were observed in our study. CONCLUSION: The prevalence of variants detected in the EXT2 gene differs from other researches from Latin America, European, and Asian population. This uncommon prevalence could be related with the newly characterized variant hotspot sites detected in EXT2 gene (p.Ala409Profs*26 and p.Ser290*). A high number of novel variants were also identified indicating that Brazilian population has a unique genetic profile. Characterizing this population and establishing its genotype is essential to understand the molecular pathogenesis of this disease in Brazil. John Wiley and Sons Inc. 2018-03-12 /pmc/articles/PMC6014457/ /pubmed/29529714 http://dx.doi.org/10.1002/mgg3.382 Text en © 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Articles
Santos, Savana C. L.
Rizzo, Isabela M. P. O.
Takata, Reinaldo I.
Speck‐Martins, Carlos E.
Brum, Jaime M.
Sollaci, Claudio
Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas
title Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas
title_full Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas
title_fullStr Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas
title_full_unstemmed Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas
title_short Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas
title_sort analysis of mutations in ext1 and ext2 in brazilian patients with multiple osteochondromas
topic Original Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014457/
https://www.ncbi.nlm.nih.gov/pubmed/29529714
http://dx.doi.org/10.1002/mgg3.382
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