A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia

We found a novel heterozygous mutation in the fibrinogen Bβ chain (c.490G>A) of a 3-year-old girl with congenital hypofibrinogenemia. To clarify the complex genetic mechanism, we made a mini-gene including a FGB c.490G>A mutation region, transfected it into a Chinese Hamster Ovary (CHO...

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Main Authors: Chiaki Taira, Kazuyuki Matsuda, Shinpei Arai, Mitsutoshi Sugano, Takeshi Uehara, Nobuo Okumura
Format: Article
Language:English
Published: MDPI AG 2017-11-01
Series:International Journal of Molecular Sciences
Subjects:
FGB
Online Access:https://www.mdpi.com/1422-0067/18/11/2470
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spelling doaj-82bb4e414a604d59898f07e1f43725ef2020-11-24T21:18:05ZengMDPI AGInternational Journal of Molecular Sciences1422-00672017-11-011811247010.3390/ijms18112470ijms18112470A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital HypofibrinogenemiaChiaki Taira0Kazuyuki Matsuda1Shinpei Arai2Mitsutoshi Sugano3Takeshi Uehara4Nobuo Okumura5Department of Health and Medical Sciences, Graduate School of Medicine, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621, JapanDepartment of Laboratory Medicine, Shinshu University Hospital, Matsumoto 390-8621, JapanDepartment of Laboratory Medicine, Shinshu University Hospital, Matsumoto 390-8621, JapanDepartment of Laboratory Medicine, Shinshu University Hospital, Matsumoto 390-8621, JapanDepartment of Laboratory Medicine, Graduate School of Medicine, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621, JapanDepartment of Health and Medical Sciences, Graduate School of Medicine, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621, JapanWe found a novel heterozygous mutation in the fibrinogen Bβ chain (c.490G>A) of a 3-year-old girl with congenital hypofibrinogenemia. To clarify the complex genetic mechanism, we made a mini-gene including a FGB c.490G>A mutation region, transfected it into a Chinese Hamster Ovary (CHO) cell line, and analyzed reverse transcription (RT) products. The assembly process and secretion were examined using recombinant mutant fibrinogen. Direct sequencing demonstrated that the mutant RT product was 99 bp longer than the wild-type product, and an extra 99 bases were derived from intron 3. In recombinant expression, a mutant Bβ-chain was weakly detected in the transfected CHO cell line, and aberrant fibrinogen was secreted into culture media; however, an aberrant Bβ-chain was not detected in plasma. Since the aberrant Bβ-chain was catabolized faster in cells, the aberrant Bβ-chain in a small amount of secreted fibrinogen may catabolize in the bloodstream. FGB c.490G>A indicated the activation of a cryptic splice site causing the insertion of 99 bp in intron 3. This splicing abnormality led to the production of a Bβ-chain possessing 33 aberrant amino acids, including two Cys residues in the coiled-coil domain. Therefore, a splicing abnormality may cause impaired fibrinogen assembly and secretion.https://www.mdpi.com/1422-0067/18/11/2470hypofibrinogenemiaFGBsplicing abnormalitycryptic splice site
collection DOAJ
language English
format Article
sources DOAJ
author Chiaki Taira
Kazuyuki Matsuda
Shinpei Arai
Mitsutoshi Sugano
Takeshi Uehara
Nobuo Okumura
spellingShingle Chiaki Taira
Kazuyuki Matsuda
Shinpei Arai
Mitsutoshi Sugano
Takeshi Uehara
Nobuo Okumura
A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia
International Journal of Molecular Sciences
hypofibrinogenemia
FGB
splicing abnormality
cryptic splice site
author_facet Chiaki Taira
Kazuyuki Matsuda
Shinpei Arai
Mitsutoshi Sugano
Takeshi Uehara
Nobuo Okumura
author_sort Chiaki Taira
title A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia
title_short A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia
title_full A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia
title_fullStr A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia
title_full_unstemmed A Novel Mutation in the Fibrinogen Bβ Chain (c.490G>A; End of Exon 3) Causes a Splicing Abnormality and Ultimately Leads to Congenital Hypofibrinogenemia
title_sort novel mutation in the fibrinogen bβ chain (c.490g>a; end of exon 3) causes a splicing abnormality and ultimately leads to congenital hypofibrinogenemia
publisher MDPI AG
series International Journal of Molecular Sciences
issn 1422-0067
publishDate 2017-11-01
description We found a novel heterozygous mutation in the fibrinogen Bβ chain (c.490G>A) of a 3-year-old girl with congenital hypofibrinogenemia. To clarify the complex genetic mechanism, we made a mini-gene including a FGB c.490G>A mutation region, transfected it into a Chinese Hamster Ovary (CHO) cell line, and analyzed reverse transcription (RT) products. The assembly process and secretion were examined using recombinant mutant fibrinogen. Direct sequencing demonstrated that the mutant RT product was 99 bp longer than the wild-type product, and an extra 99 bases were derived from intron 3. In recombinant expression, a mutant Bβ-chain was weakly detected in the transfected CHO cell line, and aberrant fibrinogen was secreted into culture media; however, an aberrant Bβ-chain was not detected in plasma. Since the aberrant Bβ-chain was catabolized faster in cells, the aberrant Bβ-chain in a small amount of secreted fibrinogen may catabolize in the bloodstream. FGB c.490G>A indicated the activation of a cryptic splice site causing the insertion of 99 bp in intron 3. This splicing abnormality led to the production of a Bβ-chain possessing 33 aberrant amino acids, including two Cys residues in the coiled-coil domain. Therefore, a splicing abnormality may cause impaired fibrinogen assembly and secretion.
topic hypofibrinogenemia
FGB
splicing abnormality
cryptic splice site
url https://www.mdpi.com/1422-0067/18/11/2470
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