摘要
目的 探讨一种F5基因新变异导致复合杂合性遗传性凝血因子Ⅴ(FⅤ)缺陷症家系的分子致病机制。方法 检测先证者及其家系成员(3代10人)的相关凝血指标。通过CAT法检测凝血酶生成量。应用直接测序法分析先证者F5基因全部外显子及其侧翼序列。使用计算机预测软件分析变异氨基酸位点的保守性及变异后对蛋白质功能的影响。根据美国医学遗传学与基因组学学会(ACMG)变异评级指南对变异位点进行评级。结果 先证者凝血酶原时间(PT)为25.2 s、活化部分凝血活酶时间(APTT)为84.4 s,均显著延长;血浆FⅤ活性(FⅤ:C)和FⅤ抗原(FⅤ:Ag)分别为6%和8%,极度降低。先证者凝血酶生成量降低和达峰时间延长。基因测序发现先证者第13外显子存在父源c.4594C>T(p.Gln1532^(*))杂合无义变异和第25外显子存在母源c.6665A>G(p.Asp2222Gly)杂合错义变异。保守性分析表明Gln1532呈高度保守;3种在线生信学软件Mutation Taster、SIFT及PolyPhen-2均显示该两种变异为有害变异;蛋白质模型分析表明p.Gln1532^(*)变异会导致FⅤ整个轻链丢失。依据ACMG变异评级指南,新变异c.4594.C>T评级为可能致病变异(PM2+PM4+PP1+PP3+PP4)。结论 F5基因第13外显子c.4594C>T杂合无义变异及第25外显子c.6665A>G杂合错义变异考虑是该FⅤ缺陷症家系的致病原因;其中F5基因c.4594C>T无义变异为国际上首次报道。
Objective To explore the molecular pathogenic mechanism of a new variant of F5 gene with a complex heterozygous hereditary coagulation factor V(FV) deficiency in a pedigree.Methods To detect the related coagulation indexes of the proband and his family members(10 persons in 3 generations).Thrombin generation was detected by CAT method.Direct sequencing was used to analyze all exons and their flanking sequences of the proband F5 gene.The conservation of amino acid variation sites and the impact of variation on protein function were analyzed by bioinformatics software.Variation sites were rated according to the American College of Medical Genetics and Genomics(ACMG) variation rating guidelines.Results The prothrombin time(PT) of the proband was 25.2 s and the activated partial thrombin time(APTT) was 84.4 s,both of which were significantly prolonged.Plasma FV activity(FV:C) and FV antigen(FV:Ag) were extremely reduced at 6% and 8%,respectively.Decreased thrombin production and prolonged peak time in the proband.Gene sequencing found that the proband had a paternal source c.4594C>T(p.Gln1532~*) heterozygous nonsense mutation in exon 13 and a maternal c.6665A>G(p.Asp2222Gly) heterozygous missense mutation in exon 25.Conversion analysis showed that Gln1532 was highly conserved.Three online bioinformatics software Mutation Taster,SIFT,and PolyPhen-2 showed that the two mutations were deleterious mutations.Protein model analysis showed that the p.Gln1532~* mutation resulted in the loss of the entire light chain of FV.According to the ACMG variant rating guidelines,the new variation c.4594.C>T was rated as a probable pathogenic variant(PM2+PM4+PP1+PP3+PP4).Conclusion The c.4594C>T heterozygous nonsense mutation in exon 13 and the c.6665A>G heterozygous missense mutation in exon 25 of the F5 gene are considered to be thepathogenesis of this FV deficiency family,of which the c.4594C>T nonsense mutation of F5 gene is first reported internationally.
作者
林双女
陈碧乐
谢耀盛
张柯
谢作听
王明山
LIN Shuangnv;CHEN Bile;XIE Yaosheng;ZHANG Ke;XIE Zuoting;WANG Mingshan(Department of Blood Transfusion,the 1th Affiliated Hospital of Wenzhou Medical University,Wenzhou,Zhejiang 325015,China;Center of Laboratory Medicine,the 1th Affiliated Hospital of Wenzhou Medical University,Wenzhou,Zhejiang 325015,China)
出处
《中国优生与遗传杂志》
2024年第2期342-346,共5页
Chinese Journal of Birth Health & Heredity
