1例遗传性抗凝血酶缺陷症导致复发性流产分析  

A case of hereditary antithrombin deficiency leading to recurrent pregnancy loss

作　　者：龚钰翔 邓雨萍 朱嘉晋 周星星[2] 王明山[2] 吴文鹤[1] GONG Yuxiang;DENG Yuping;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,浙江温州325035 [2]温州医科大学附属第一医院医学检验中心,浙江温州325015

出　　处：《中国优生与遗传杂志》2021年第1期84-87,共4页Chinese Journal of Birth Health & Heredity

基　　金：国家自然科学基金(81670712);温州市科技计划基金(Y20190464)。

摘　　要：目的对1个新的SERPINC1基因杂合错义突变导致遗传性抗凝血酶缺陷症家系进行表型和基因突变分析,探讨此基因突变与复发性流产的关系。方法收集先证者及其家系成员临床资料(共3代5人);检测先证者及家系成员的抗凝血酶活性(antithrombin activity,AT:A)、抗凝血酶抗原(antithrombin antigen,AT:Ag)、蛋白C活性(protein C activity,PC:A)、蛋白S活性(protein S activity,PS:A)等指标。抽提外周血基因组DNA进行PCR扩增,采用Sanger测序法检测先证者SERPINC1基因的所有外显子、侧翼序列、5′和3′端非翻译区及家系成员相应的突变区域。用Clusta LX-2.1-win软件分析突变位点基因的保守性,用Mutation Taster和PolyPhen-2在线生物信息学软件评价突变的危害性,并采用Swiss-Pdb Viewer软件分析突变前后蛋白质空间结构及分子间作用力。结果先证者和其女儿常规凝血指标及PC:A、PS:A、AT:Ag均正常,但AT:A分别降低为63%和58%(正常参考范围:98%~119%)。基因分析显示,先证者和其女儿SERPINC1基因第7外显子均存在c.1346T>A杂合错义突变,导致p.Leu449Gln。保守性分析表明Leu449在同源物种间呈高度保守;MutationTaster和PolyPhen-2软件对p.Leu449Gln的评分结果都为1.000分,预测此杂合错义突变很可能是有害突变;突变蛋白模型分析显示:野生型AT蛋白中,非极性的Leu449主链与Glu444的主链形成一个氢键;当突变为极性的Gln449后,原有的氢键未改变,但其与Thr451增加了1个氢键,导致蛋白质结构改变。结论该先证者出现复发性流产,可能与p.Leu449Gln杂合错义突变有关。Objective To analyze the phenotype and gene mutation of a novel SERPINC1 heterozygous missense mutation which caused hereditary antithrombin deficiency, and explore the relationship between the mutant gene and recurrent pregnancy loss. Methods The clinical data were collected and the antithrombin activity(AT:A), antithrombin antigen(AT:Ag), protein C activity(PC:A), protein S activity(PS:A) and other coagulation indicators were analyzed for the proband and her family members(3 generations of 5 people). Their peripheral blood genomic DNA was extracted for PCR amplification. Sanger sequencing was used to detect all the exons\flanking sequences, 5’ and 3’ untranslated region of the proband’s SERPINC1 gene and corresponding mutation regions of family members. The conservation of the mutation site gene was analyzed by ClustaLX-2.1-win. Both Mutation Taster and PolyPhen-2 were used to evaluate the harmfulness of the mutation. The protein spatial structure and intermolecular forces before and after the mutation were assessed by Swiss-Pdb Viewer. Results The routine coagulation indicators and the PC:A, PS:A, AT:Ag of proband and her daughter were all in the normal range, except the AT:A reduced to 63% and 58%, respectively. Their genetic analysis showed that there was a same heterozygous missense mutation c.1346 T>A in exon 7 of their SERPINC1 gene, which resulted in p.Leu449 Gln. Conservation indicated that Leu449 was highly conserved among homologous species. The scores of p.Leu449 Gln by Mutation Taster and PolyPhen-2 software were both 1.000, which predicts that this heterozygous missense mutation was likely to be deleterious. The protein model analysis showed that the Leu449, a non-polar amino acid, formed a hydrogen bond with Glu444 in wild-type;when Leu449 was replaced by polar Gln449, the original hydrogen bond with Glu444 was remained and another hydrogen bond was formed with Thr451, which may change the structure of protein. Conclusion The occurrence of recurrent pregnancy loss in this proband may be rela

关 键 词：遗传性抗凝血酶缺陷症 基因突变 血栓形成 复发性流产 

分 类 号：R714.21[医药卫生—妇产科学]