纯合子Cys329Gly导致的遗传性凝血因子Ⅶ缺陷症家系基因突变分析  

An inherited coagulation factor Ⅶ deficiency pedigree caused by homozygous mutation of Cys329Gly

作　　者：苏正仙[1] 张慧斐[1] 金艳慧[2] 程晓丽[2] 王明山[2] 沈波[1] 

机构地区：[1]浙江省台州医院检验科,浙江台州317000 [2]温州医科大学附属第一医院,浙江温州325025

出　　处：《中国优生与遗传杂志》2016年第8期21-23,F0002,共4页Chinese Journal of Birth Health & Heredity

基　　金：温州市科技局计划项目(Y20150302)

摘　　要：目的对1个姨表近亲婚配的遗传性凝血因子Ⅶ(FⅦ)缺陷症家系进行表型和F7基因突变分析,探讨其分子发病机制。方法检测先证者及其家系成员(共4代9人)凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、纤维蛋白原(FIB)、血浆FⅦ活性(FⅦ:C)等来明确诊断。PCR扩增先证者全部外显子及其侧翼序列、5′和3′非翻译区及家系成员相应的突变位点区域,PCR产物纯化后直接测序,寻找突变位点,以反向测序验证所发生的突变;使用生物信息学软件(Poly Phen-2和Mutation Taster)预测突变位点对蛋白质功能的影响,利用Py MOL软件构建正常FⅦ蛋白空间模型,进行定点突变观察构型改变。结果先证者PT(36.1s)和FⅦ:C(2%)明显异常,家系中其余8位成员PT均略高于正常对照组和FⅦ:C均略低于正常对照组;基因分析显示先证者F7基因第8外显子存在c.1165 T>G纯合型突变,即TGT→GGT(Cys329Gly),8位家系成员的F7基因分析均显示c.1165有杂合型突变;两种生物信息学软件都提示此突变会引起蛋白功能变化,有致病性;F7基因蛋白构型显示突变后329位点与310位点之间二硫键消失,周边静电磁场发生改变。结论该家系F7基因存在Cys329Gly突变,是引起FⅦ缺陷症的主要分子机制,推测先证者纯合Cys329Gly突变基因分别遗传自近亲结婚的杂合子父母。Objective： To explore the gene mutation and the molecular pathogenesis of inherited coagulation factorⅦ （FⅦ） deficiency in a pedigree with consanguineous marriage. Methods： The prothrombin time （PT） , activated partial thromboplastin time （APTT） , fibrinogen （FIB） and coagulation factor VII activity （FVII： C） were assayed to make a definite diagnosis. All exons, exon-intron boundaries and 5＇ and 3＇ untranslated sequences of F7 were screened by PCR and direct sequencing. Suspected mutations were confirmed by sequencing the opposite strand. Three bioinformatics online softwares （PolyPhen-2 and Mutation Taster） were used to predict the possible impact of the mutation on the protein function. A PyMOL software was used to analysis the model of mutation site. Results： The proband＇ s values of PT and FⅦ： C were obvious abnormal which were 36.1s and 2% separately. A homozygous mutation c. 1165 T〉G in exon 8 of F7 was found in the proband which resulting in Cys329Gly. And eight other members of this famly had a heterozygous mutation c.1165 T〉G. The prothrombin time （PT） of these eight members were slightly higher than that of the normal control group. While the FⅦactivity were slightly lower than the normal control group. Both results of two bioinformatics softwares suggest that this mutation will make changes in function of protein. Protein model analysis indicated that the disulfide bond between site-329 and site-310 was disappeared, and the surrounding electrostatics changed. Conclusion： Missense mutation of C329G was discovered in a pedigree of hereditary FⅦ deficiency. The mutation was inherited from his heterozygote parents.

关 键 词：遗传性凝血因子Ⅶ缺乏症 基因突变 血液凝固障碍 

分 类 号：R554[医药卫生—血液循环系统疾病]