Compound heterozygous mutations identified in severe type I protein S deficiency impaired the secretion of protein S
Compound heterozygous mutations identified in severe type I protein S deficiency impaired the secretion of protein S
复制标题
在严重的 I 型蛋白 S 缺乏症中发现的复合杂合突变损害了蛋白 S 的分泌
DOI：
10.1136/jclinpath-2019-205956
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发表时间：
2020
影响因子：
3.4
通讯作者：
Shen Wei
中科院分区：
文献类型：
--
作者：
Zhou Jingyi;Shen Wenyan;Gu Yi;Li Min;Shen Wei
遗传性蛋白S（PS）缺乏症是引起血栓形成倾向的天然抗凝物质缺乏症之一。我们在此描述一位年轻男性，患有复发性深静脉血栓形成，被诊断为I型PS缺乏症，并伴有PROS1基因的复合杂合突变。本研究旨在分析基因型与表型检测之间的关系，探讨引起PS缺陷的PROS1基因突变的病理机制。凝血酶生成试验（TGT）检测血浆PS对凝血酶生成的抑制作用及凝血酶生成潜能。实时荧光定量PCR检测突变体PS的mRNA转录水平，Western blot和ELISA检测突变体PS的蛋白水平。结果在先证者中发现了复合杂合突变（PROS1c.1551_1552delinsG，p.Thr518Argfs * 39和PROS1c.1681C> T，p.Arg561Trp），其中前者为一种新的小indel突变。TGT结果显示，在他的父母与某些杂合突变的凝血酶生成的抑制受损的活化蛋白C的添加。在体外表达研究中，p.Thr518Argfs * 39突变体产生的截短蛋白滞留在胞质中，而p.Arg561Trp突变体部分影响PS的分泌。这两种突变都位于PS的C-末端性激素结合球蛋白（SHBG）样结构域。PS的SHBG样结构域可能在PS分泌系统中起重要作用。
AimsHereditary protein S (PS) deficiency is one of the natural anticoagulant deficiencies causing thrombophilia. We herein described a young male with recurrent deep venous thrombosis, who was diagnosed as type I PS deficiency with compound heterozygous mutations ofPROS1gene. We aimed to analyse the relationship between the genotype and phenotype detection and investigate the pathological mechanisms ofPROS1mutations causing PS deficiency.MethodsGenetic analysis ofPROS1gene was carried out by direct sequencing. Thrombin generation potential and the inhibition function of thrombin generation by plasma PS were detected by thrombin generation test (TGT). The mRNA transcription level of mutant PS in vitro was measured by real-time PCR, while the protein level was evaluated by western blot and ELISA. Cellular distribution of the protein was further analysed by immunofluorescence.ResultsCompound heterozygous mutations (PROS1c.1551_1552delinsG, p.Thr518Argfs*39 andPROS1c.1681C>T, p.Arg561Trp) were identified in the propositus, and the former one was a novel small indel mutation. TGT results showed impaired inhibition of thrombin generation with the addition of activated protein C in his parents with certain heterozygous mutations. In vitro expression study, p.Thr518Argfs*39 mutant produced truncated protein retained in the cytoplasm, while p.Arg561Trp mutant partially affected the secretion of PS. Both mutations are located in C-terminal sex hormone-binding globulin (SHBG)-like domain of PS.ConclusionsCompound heterozygous mutations identified in the study have strong detrimental effect, causing severe type I PS deficiency in the propositus. SHBG-like domain of PS might play an important role in PS secretion system.