2个复合杂合变异致遗传性低且异常纤维蛋白原血症家系分析  

Analysis of two pedigrees with congenital hypodysfibrinogenemia caused by two compound heterozygous variations

作　　者：徐琦煜[1] 郑晓勇 徐斐[1] 叶龙颖 张柯 王明山[1] 杨丽红[1] XU Qiyu;ZHENG Xiaoyong;XU Fei;YE Longying;ZHANG Ke;WANG Mingshan;YANG Lihong(Department of Clinical Laboratory,The First Affiliated Hospital of Wenzhou Medical University,Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province,Wenzhou 325015,Zhejiang,China)

机构地区：[1]温州医科大学附属第一医院医学检验中心,浙江省检验诊断及转化研究重点实验室,浙江温州325015

出　　处：《临床检验杂志》2025年第2期92-97,共6页Chinese Journal of Clinical Laboratory Science

基　　金：浙江省检验诊断及转化研究重点实验室(2022E10022);温州市科技计划基金(Y20220746)。

摘　　要：目的 对2个由复合杂合变异导致的遗传性低且异常纤维蛋白原(Fg)血症家系进行表型和基因变异分析,并初步探讨其分子致病机制。方法 分别选取2023年5月4日和2023年5月20日因“帕金森”和“双眼皮切割术前”就诊于温州医科大学附属第一医院的先证者A和B及其家系成员(均3代共19人)均3代的家系A和家系B作为研究对象。采用凝固法分别检测2个家系成员的凝血酶时间(TT)和Fg活性(Fg:C),并采用免疫比浊法检测Fg抗原(Fg:Ag),利用人凝血酶催化进行Fg聚集试验,并对FGG基因进行PCR扩增和一代测序。用Chromas软件分析变异位点。利用ClustalX-2.1-win软件进行多序列比对;使用生物信息学软件进行变异位点致病性分析;使用PyMOL软件进行FGG蛋白模型分析。结果 表型结果显示先证者A和B的TT分别延长至27.5 s和26.1 s,血浆Fg:C分别降至0.6 g/L和<0.5 g/L。基因测序发现2个先证者在FGG基因第8内含子上均存在杂合c.1129+62_65delAATA,使p.γGly377-Gly388形成异常氨基酸,并在p.γTyr389位点提前形成终止密码子;同时先证者A的FGA基因第2外显子发现存在c.103C>A杂合错义变异(p.AαArg35Ser),先证者B的FGB基因第4外显子发现存在c.569A>G杂合错义变异(p.BβAsn190Ser)。2名先证者Fg聚集峰值和速率相较于对照组均有明显下降。多序列比对分析显示3个变异位点均保守。3种生物信息学软件预测2种错义变异均为致病变异。蛋白建模分析显示p.γGly377-Gly388变异区域的氢键数量发生改变,产生了空间位阻。结论 2种复合杂合变异c.1129+62_65delAATA和p.AαArg35Ser、c.1129+62_65delAATA和p.BβAsn190Ser均为国内外首次报道,且这3种变异可能与2个家系Fg水平和功能降低有关。Objective To analyse phenotype and genetic variation of two congenital hypodysfibrinogenemia(Fg)caused by compound heterozygous variants and preliminary investigate their molecular pathogenic mechanisms.Metheds The proband A and B and their family members(a total of 19 members in 3 generations)who visited the First Hospital of Wenzhou Medical University on 4 May 2023 and 20 May 2023 for“parkinson's disease”and“pre-bilateral eyelid excision”were enrolled for the study.Prothrombin time(TT)and fibrinogen(Fg)activity were measured by coagulation assay and Fg antigen(Fg:Ag)was measured by immunoturbidimetric assay for the two family members,and Fg aggregation assay was catalysed using human thrombin.FGG gene was amplified by PCR and sequenced directly.The variant sites were analysed using Chromas software.Multiple sequence comparison was performed by ClustalX-2.1-win software.Pathogenicity analysis of the variant sites was performed using bioinformatics software.The analysis for FGG protein model was performed using PyMOL software.Results Phenotypic results showed TT of proband A and B extended to 27.5 s and 26.1 s,and plasma Fg activity reduced to 0.6 g/L and<0.5 g/L,respectively.Genetic sequencing identified heterozygous c.1129+62_65delAATA on intron 8 of FGG gene in the both probands,resulting in the formation of aberrant amino acids at p.Gly377-Gly388 and an early termination codon at p.Tyr389 site.A heterozygous missense variant c.103C>A(p.AαArg35Ser)was found in exon 2 of the FGA gene of proband A,and a heterozygous missense variant c.569A>G(p.BβAsn190Ser)was found in exon 4 of the FGB gene of proband B.Compared to the control group,the both probands showed significant decreases in peak and rate of Fg aggregation.Multiple sequence comparison analyses showed that all the three variant sites were conserved.Three bioinformatics software predicted both the missense variants were pathogenic.Protein modelling analysis showed that the number of hydrogen bonds in p.Gly377-Gly388 variant region was altered,resu

关 键 词：遗传性低且异常纤维蛋白原血症 基因测序 纤维蛋白原聚集试验 生物信息学 

分 类 号：R446[医药卫生—诊断学]