一个复合杂合变异致遗传性凝血因子Ⅺ缺陷症家系分析  

Analysis of hereditary coagulation factorⅪdeficiency in a Chinese pedigree with compound heterozygous mutations

作　　者：邓雨萍 龚钰翔 朱嘉晋 周星星[2] 王明山[2] 吴文鹤[1] Deng Yuping;Gong Yuxiang;Zhu Jiajin;Zhou Xingxing;Wang Mingshan;Wu Wenhe(Key Laboratory of Laboratory Medicine,Ministry of Education,School of Laboratory Medicine and Life Sciences,Wenzhou Medical University,Wenzhou,Zhejiang 325035,China;Department of Clinical Laboratory,The First Affiliated Hospital of Wenzhou Medical University,Wenzhou,Zhejiang 325015,China)

机构地区：[1]温州医科大学检验医学院(生命科学学院)检验医学教育部重点实验室,温州325035 [2]温州医科大学附属第一医院医学检验中心,温州325015

出　　处：《中华医学遗传学杂志》2022年第6期592-596,共5页Chinese Journal of Medical Genetics

基　　金：国家自然科学基金(81670712);温州市科技局项目(Y2020110)。

摘　　要：目的探讨一个遗传性凝血因子XI(coagulation factorⅪ,FⅪ)缺陷症家系成员的分子致病机制。方法提取外周血基因组DNA,并采用Sanger测序法检测先证者的15个外显子、侧翼序列及家系成员的相应变异外显子区域,并用反向测序予以验证;ClustalX-2.1-win软件分析变异氨基酸位点的保守性;用Mutation Taster、PolyPhen2、PROVEAN三个在线生物信息学软件分析变异的致病性;用Swiss-pdbViewer软件分析变异氨基酸对蛋白质结构的影响。结果基因分析显示先证者第10外显子存在c.1107C>A(p.Tyr369stop)杂合无义变异以及第13外显子存在c.1562A>G(p.Tyr521Cys)杂合错义变异;其父亲携带c.1107C>A杂合无义变异,其母亲和女儿均携带c.1562A>G杂合错义变异,丈夫为野生型。保守性分析表明Tyr521在进化过程中为高度保守位点。变异碱基致病性预测发现c.1107C>A和c.1562A>G均为致病性变异。蛋白质模型分析显示在野生型FⅪ蛋白结构中,Tyr521分别与Lys572、Ile388形成一个氢键,当变异为Cys521后,原有的苯环结构消失,并且与Lys572的侧链增加了一个氢键,改变了蛋白的催化结构域;p.Tyr369stop变异形成截短蛋白,这些变化均可能使蛋白质的功能受到影响。结论该家系第10外显子c.1107C>A杂合无义变异以及第13外显子c.1562A>G杂合错义变异是导致该家系FⅪ水平降低的主要原因。Objective To explore the molecular mechanisms of a Chinese pedigree with hereditary factorⅪ(FⅪ)deficiency.Methods All of the 15 exons,flanking sequences of the FⅪgene and the corresponding mutation sites of family members were analyzed by the Sanger sequencing,followed by the extraction of the peripheral blood genomic DNA.And all the results were verified by the reverse sequencing.The conservation of the mutated sites was analyzed by the ClustalX-2.1-win.Three online bioinformatics software tools,including Mutation Taster,PolyPhen2 and the PROVEAN,were used to assess the possible impact of the mutations.Swiss-pdbviewer software was used to analyze the effects of mutant amino acids on protein structure.Results Genetic analysis revealed that the proband had compound heterozygous mutations including a nonsense mutation of c.1107C>A(Tyr369stop)in exon 10 and missense mutation of c.1562A>G(Tyr521Cys)in exon 13.The same c.1107C>A(Tyr369stop)was present in her father,the same c.1562A>G(Tyr521Cys)was present in both her mother and daughter.Conservation analysis indicated that Tyr521 was a highly conserved site during evolution.The prediction of pathogenicity showed that both c.1107C>A and c.1562A>G were pathogenic mutations.Protein structure prediction showed that in the wild type FⅪprotein structure,Tyr521 formed a hydrogen bond with the Lys572 and Ile388,respectively.When Tyr521 was replaced by Cys521,the original benzene ring structure disappeared,and side chains of Lys572 added a hydrogen bond with the Cys521,which may chang protein catalytic domain structure.When Tyr369 was mutated to a stop codon,resulting in the truncated protein.Conclusion The compound heterozygous mutations including the c.1107C>A heterozygous missense variant in exon 10 and the c.1562A>G heterozygous nonsense mutation in exon 13 may be responsible for the hereditary factorⅪdeficiency in this Chinese pedigree.

关 键 词：凝血因子Ⅺ缺陷症 分子遗传学 生物信息学 

分 类 号：R554[医药卫生—血液循环系统疾病] R440[医药卫生—内科学]