PDF(Pubmed)
Abstract：
BACKGROUND: This study aims to analyze the pathogenic gene in a Chinese family with non-syndromic hearing loss and identify a novel mutation site in the TNC gene.
METHODS: A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis.
RESULTS: The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A > T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5\' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19.
CONCLUSIONS: This novel splice-altering variant (c.5247A > T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.
METHODS: A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis.
RESULTS: The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A > T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5\' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19.
CONCLUSIONS: This novel splice-altering variant (c.5247A > T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.
摘要：
背景：本研究旨在分析一个非综合征性听力损失的中国家庭中的致病基因，并鉴定TNC基因中的新突变位点。
方法：安徽省五代中国家庭，表现为常染色体显性遗传的非综合征性听力损失，被招募参加这项研究。通过分析家族史，进行临床检查，进行基因分析，我们已经彻底调查了这个家族的潜在致病因素。外周血样本来自20名家庭成员，通过全外显子组测序鉴定致病基因。随后，使用Sanger测序证实了基因位点的突变。使用ClustalOmega软件评估TNC突变位点的保守性。我们使用了功能预测软件，包括dbscSNV_AdaBoost，dbscSNV_RandomForest,NNSplice,NetGene2和MutationTaster可以准确预测这些突变的致病性。此外，通过RT-PCR分析验证外显子缺失.
结果：该家族表现出常染色体显性遗传，进步,后语言，非综合征性听力损失。一种新的同义词变体(c.5247A>T，在受影响的成员中鉴定出TNC中的p.Gly1749Gly）。该变体位于朝向外显子18末端的外显子-内含子连接边界处。值得注意的是,在位置1749的甘氨酸残基在各种物种中是高度保守的。生物信息学分析表明，这种同义突变导致TNC基因第18内含子中5'末端供体剪接位点的破坏。同时,验证实验表明，这种同义突变破坏了外显子18的剪接过程，导致外显子18完全跳跃和外显子17和19之间的直接剪接。
结论：这种新颖的剪接改变变体（c.5247A>T，TNC基因外显子18中的p.Gly1749Gly）破坏了正常的基因剪接，并导致HBD家族中的听力损失。
方法：安徽省五代中国家庭，表现为常染色体显性遗传的非综合征性听力损失，被招募参加这项研究。通过分析家族史，进行临床检查，进行基因分析，我们已经彻底调查了这个家族的潜在致病因素。外周血样本来自20名家庭成员，通过全外显子组测序鉴定致病基因。随后，使用Sanger测序证实了基因位点的突变。使用ClustalOmega软件评估TNC突变位点的保守性。我们使用了功能预测软件，包括dbscSNV_AdaBoost，dbscSNV_RandomForest,NNSplice,NetGene2和MutationTaster可以准确预测这些突变的致病性。此外，通过RT-PCR分析验证外显子缺失.
结果：该家族表现出常染色体显性遗传，进步,后语言，非综合征性听力损失。一种新的同义词变体(c.5247A>T，在受影响的成员中鉴定出TNC中的p.Gly1749Gly）。该变体位于朝向外显子18末端的外显子-内含子连接边界处。值得注意的是,在位置1749的甘氨酸残基在各种物种中是高度保守的。生物信息学分析表明，这种同义突变导致TNC基因第18内含子中5'末端供体剪接位点的破坏。同时,验证实验表明，这种同义突变破坏了外显子18的剪接过程，导致外显子18完全跳跃和外显子17和19之间的直接剪接。
结论：这种新颖的剪接改变变体（c.5247A>T，TNC基因外显子18中的p.Gly1749Gly）破坏了正常的基因剪接，并导致HBD家族中的听力损失。
