摘要
目的对1个姑表近亲婚配的遗传性凝血因子X（coagulation factor X，FX）缺陷症家系进行基因突变检测，探讨F10基因突变与表型的关系。方法应用ELISA法检测先证者及家系成员的FX抗原（FX antigen，FX：Ag），一期凝固法检测其凝血酶原时间（prothrombin time，PT）、活化部分凝血活酶时间（activated partial thromboplastin time，APTT）、纤维蛋白原（fibrinogen，FIB）、血浆FX活性（FX activity，FX：C）等指标以明确诊断；用DNA测序法分析先证者F10基因的全部外显子及侧翼序列、5’和3’非翻译区及家系成员相应的突变位点区域；用CLC Genomics Workbench 7．5软件分析基因突变位点的物种保守性和蛋白质二级结构改变。结果先证者PT、APTT、FX：C和FX：Ag均明显异常，分别为67．2s、102．9s、1％、8％；先证者父亲、母亲和弟弟PT稍延长，分别为14．5s、14．4s和14．4s，其FX：C（54％、48％和56％）和FX：Ag（52％、54％和54％）均较正常对照水平降低；其他家系成员的凝血表型指标均在正常范围。先证者F／0基因第8外显子的g．27881G〉A纯合突变导致p．Va1298Met，其父亲、母亲和弟弟均为g．27881G〉A杂合子，先证者的g．27881G〉A纯合突变分别遗传自近亲婚配的父母，先证者妹妹F10基因为正常野生型。蛋白质生物学特性分析发现，p．Va1298Met导致FX蛋白二级结构发生改变。结论该遗传性FX缺陷症家系先证者的F10基因存在g．27881G〉A（p．Va1298Met）纯合错义突变，且与该家系FX水平降低有关。
Objective To identify potential mutation underlying congenital factor X （FX） deficiency in a consanguineous Chinese pedigree. Methods Prothrombin time（PT）, activated partial thromboplastin time（APTT）, fibrinogen, FX activity（FX ：C） and other coagulant parameters were determined with a one- stage clotting assay. The FX antigen（FX ：Ag） was determined with an ELISA assay. All coding exons and exon-intron boundaries of the FIO gene were amplified with PCR and subjected to direct sequencing. Suspected mutation was confirmed by reverse sequencing and analyzed with CLC Genomics Workbench 7.5 software. Results The PT and APTT in the proband were prolonged to 67.2 s and 102.9 s, respectively. Further study showed that her F X ：C and F X ：Ag were reduced by 1% and 8 %, respectively. The PT of her father, mother, and little brother were slightly prolonged to 14.5 s, 14.4 s and 14.4 s, respectively. The FX ：C and FX ：Ag in her father, mother and little brother were all slightly reduced. Genetic analysis of the proband has revealed a homozygous G〉A change at nucleotide 27881 in exon 8 of the FIO gene, which predicted a p. Va1298Met substitution. The proband＇ s father, mother, and little brother were all heterozygous for the p. Va1298Met mutation. The proband has inherited the homozygous mutation from her parents by consanguineous marriage. Other family members were all normal. Bioinformatics analysis has indicated that this mutation may result in changes in the secondary structure of the FN protein. Conclusion A homozygous mutation g. 27881G〉A（p. Va1298Met） of the FIO gene has been identified, which probably accounts for the low FX concentrations in this pedigree.
出处
《中华医学遗传学杂志》
CAS
CSCD
北大核心
2016年第3期296-299,共4页
Chinese Journal of Medical Genetics
基金
温州市科技计划项目（Y20100284）
关键词
近亲结婚
因子X缺乏症
遗传性血液凝集障碍
基因突变
Consanguineous marriage
Factor X deficiency
Inherited blood coagulation disorder
Gene mutation
