八例血小板无力症的基因突变特征分析

摘要

目的 分析8例血小板无力症患者的基因测序结果,结合临床表现、实验室检查探讨其发病机制.方法 收集2007至2018年于北京大学第一医院通过血小板聚集试验以及流式细胞术检测血小板表面CD41和CD61表达诊断为血小板无力症的8例患者及其中4个家系,通过下一代测序法检测整合素αⅡb、β3基因的所有外显子及其侧翼序列,以及血小板型出血性疾病相关基因,突变位点采用一代测序验证,经检索HGMD、PubMed数据库及相关文献排除多态性可能.结果 8例患者血小板计数基本正常,凝血功能正常,血小板对二磷酸腺苷反应低下,对瑞斯托霉素反应基本正常;8例患者中5例血小板表面αⅡb/β3低于正常值的5％,2例为正常的5％～20％,1例与健康人相比数量未见减少.发现5种发生于ITGA2B基因的突变,分别为c.1750C ＞T(p.Arg584Ter)、c.1882C＞T(p.Arg628Ter)、c.814G＞ C(p.Va1272Leu)、c.2333A＞ C(p.Gln778Pro)、c.432G＞A(p.Trp144Ter).发现6种发生于ITGB3基因的突变,分别为c.719G ＞A(p.Arg240 Gin)、c.2248C＞ T(p.Arg750Ter)、c.1495T＞C(p.Cys499Arg)、c.1728delC(p.Ser577ProfsTer92)、c.877C＞T(p.Gln293Ter)、c.1260G＞A.另外,发现血小板无力症患者中存在RUNX1、HPS4、MYH9、ACTN1、HPS3以及SETBP1等基因突变.结论 血小板无力症患者中杂合突变,特别是复合杂合突变更多见;血小板无力症的发病不排除有除ITGA2B基因和ITGB3基因外RUNX1等基因突变参与的可能.%Objective To analyze the gene sequencing in eight patients with Glanzmann's thromboasthenia(GT),and combined with clinical manifestations and laboratory findings to investigate the molecular mechanism of GT.Methods Eight patients who were diagnosed as GT based on platelet aggregation test and flow cytometry were enrolled,as well as 4 pedigrees.Next-generation sequencing was used to analyze all the exons and flanking sequences of α Ⅱ band β3 gene and also platelet-type bleeding disorders related genes.Gene polymorphism was excluded by retrievaling HGMD and PubMed databases and relative literature.Mutations were confirmed by sanger sequencing.Results All the eight patients had relatively normal platelet counts and coagulation profiles.But their platelet response to ADP was impaired,and their platelet response to ristocetin was relatively normal.Flow cytometry showed that of the 8 patients,platelet surface α Ⅱ b/β3 was lower than 5％ of the normal value in 5 cases,and in 2 cases was 5％ to 20％ of normal value,and in 1 case there was no significant platelet surface α Ⅱ b/β3 reduction compared with normal level.Gene analysis revealed that five mutations in ITGA2B gene were identified,including c.1750C ＞ T (p.Arg584Ter),c.1882C ＞ T (p.Arg628Ter),c.814G ＞ C (p.Va1272Leu),c.2333A ＞ C (p.Gln778Pro),c.432G ＞A(p.Trp144Ter).Six mutations in ITGB3 gene,including c.719G ＞ A(p.Arg240Gln),c.2248C ＞ T (p.Arg750Ter),c.1495T ＞ C (p.Cys499Arg),c.1728delC (p.Ser577ProfsTer92),c.877C ＞ T (p.Gln293Ter),c.1260G ＞ A were identified.In addition,mutations in genes such as RUNX1,HPS4,MYH9,ACTN1,HPS3 and SETBP1 were identified in patients with GT.Conclusions Rather than homozygous mutations,heterozygous mutations,especially compound heterozygous mutations,are more common in patients with GT.The pathogenesis of GT may relate to gene mutations such as RUNX1 in addition to the ITGA2B gene and the ITGB3 gene.