FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations

Background: Congenital contractural arachnodactyly (CCA) is a rare autosomal dominant connective tissue disorder caused by mutations in the fibrillin-2 (FBN2) gene, characterized by crumpled ears, arachnodactyly, camptodactyly, dolichostenomelia, large-joint contractures and thoracolumbar scoliosis....

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Main Authors: Yazhou Huang, Xingxin Fang, Linya Ma, Jibo Zhang, Chao Wang, Taoran Gao, Dan Peng
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Molecular Genetics and Metabolism Reports
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214426925000084
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author Yazhou Huang
Xingxin Fang
Linya Ma
Jibo Zhang
Chao Wang
Taoran Gao
Dan Peng
author_facet Yazhou Huang
Xingxin Fang
Linya Ma
Jibo Zhang
Chao Wang
Taoran Gao
Dan Peng
author_sort Yazhou Huang
collection DOAJ
description Background: Congenital contractural arachnodactyly (CCA) is a rare autosomal dominant connective tissue disorder caused by mutations in the fibrillin-2 (FBN2) gene, characterized by crumpled ears, arachnodactyly, camptodactyly, dolichostenomelia, large-joint contractures and thoracolumbar scoliosis. Variations in the FBN2 gene primarily include missense mutations and splice sites mutations. It is crucial to clarify whether missense mutations in the FBN2 gene affect mRNA splicing. Methods: We identified a novel pathogenic missense variant (c.3472G > C, p.Asp1158His) in exon 26 of the FBN2 gene using whole-exome sequencing (WES) and Sanger sequencing. In vitro, both the wild-type and mutant minigenes were successfully inserted into the pcMINI and pcMINI-C vectors to verify the impact of this variant on FBN2 mRNA splicing. We utilized CLUSTALW to perform multiple sequence alignment to compare the evolutionary conservation of this variant and employed AlphaFold2 to predict the protein structure of the mutant. Results: The likely pathogenic missense mutation (c.3472G > C) results in the amino acid at position 1158 of the FBN2 changing from aspartic acid (Asp) to histidine (His). Furthermore, DNA multiple sequence alignment indicates that this site is highly evolutionarily conserved. Functional assays and structure prediction indicated that the missense variant located at the edge of exon 26 of FBN2 does not affect RNA splicing, instead, it changes the structure and function of the protein by altering the amino acid sequence. Conclusion: This study enriches the pathogenic spectrum of CCA. Our research provides new insights for the diagnosis of CCA and may have an impact on genetic counseling.
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spelling doaj-art-10b8f9ed0b31486eb8751036dba48b0e2025-08-20T02:04:15ZengElsevierMolecular Genetics and Metabolism Reports2214-42692025-03-014210119310.1016/j.ymgmr.2025.101193FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestationsYazhou Huang0Xingxin Fang1Linya Ma2Jibo Zhang3Chao Wang4Taoran Gao5Dan Peng6Department of Medical Genetics, Changde Hospital, Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City), 818 Renmin Road, Wuling District, Changde, Hunan 415000, ChinaDepartment of Medical Genetics, Changde Hospital, Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City), 818 Renmin Road, Wuling District, Changde, Hunan 415000, ChinaDepartment of Medical Genetics, Changde Hospital, Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City), 818 Renmin Road, Wuling District, Changde, Hunan 415000, ChinaDepartment of Medical Genetics, Changde Hospital, Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City), 818 Renmin Road, Wuling District, Changde, Hunan 415000, ChinaDepartment of Medical Genetics, Changde Hospital, Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City), 818 Renmin Road, Wuling District, Changde, Hunan 415000, ChinaHengyang Medical School, University of South China, Hengyang 421000, ChinaDepartment of Medical Genetics, Changde Hospital, Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City), 818 Renmin Road, Wuling District, Changde, Hunan 415000, China; Corresponding author.Background: Congenital contractural arachnodactyly (CCA) is a rare autosomal dominant connective tissue disorder caused by mutations in the fibrillin-2 (FBN2) gene, characterized by crumpled ears, arachnodactyly, camptodactyly, dolichostenomelia, large-joint contractures and thoracolumbar scoliosis. Variations in the FBN2 gene primarily include missense mutations and splice sites mutations. It is crucial to clarify whether missense mutations in the FBN2 gene affect mRNA splicing. Methods: We identified a novel pathogenic missense variant (c.3472G > C, p.Asp1158His) in exon 26 of the FBN2 gene using whole-exome sequencing (WES) and Sanger sequencing. In vitro, both the wild-type and mutant minigenes were successfully inserted into the pcMINI and pcMINI-C vectors to verify the impact of this variant on FBN2 mRNA splicing. We utilized CLUSTALW to perform multiple sequence alignment to compare the evolutionary conservation of this variant and employed AlphaFold2 to predict the protein structure of the mutant. Results: The likely pathogenic missense mutation (c.3472G > C) results in the amino acid at position 1158 of the FBN2 changing from aspartic acid (Asp) to histidine (His). Furthermore, DNA multiple sequence alignment indicates that this site is highly evolutionarily conserved. Functional assays and structure prediction indicated that the missense variant located at the edge of exon 26 of FBN2 does not affect RNA splicing, instead, it changes the structure and function of the protein by altering the amino acid sequence. Conclusion: This study enriches the pathogenic spectrum of CCA. Our research provides new insights for the diagnosis of CCA and may have an impact on genetic counseling.http://www.sciencedirect.com/science/article/pii/S2214426925000084Congenital contractural arachnodactylyFBN2Whole-exome sequencingSanger sequencingSplicing
spellingShingle Yazhou Huang
Xingxin Fang
Linya Ma
Jibo Zhang
Chao Wang
Taoran Gao
Dan Peng
FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
Molecular Genetics and Metabolism Reports
Congenital contractural arachnodactyly
FBN2
Whole-exome sequencing
Sanger sequencing
Splicing
title FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
title_full FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
title_fullStr FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
title_full_unstemmed FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
title_short FBN2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
title_sort fbn2 pathogenic mutation in congenital contractural arachnodactyly with severe skeletal manifestations
topic Congenital contractural arachnodactyly
FBN2
Whole-exome sequencing
Sanger sequencing
Splicing
url http://www.sciencedirect.com/science/article/pii/S2214426925000084
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