Novel p.C252G and p.C280X mutations in EGF-1 domain of thrombomodulin lead to a thrombosis-bleeding syndrome.

IF 5.5 2区医学 Q1 HEMATOLOGY

Journal of Thrombosis and Haemostasis Pub Date : 2025-05-23 DOI:10.1016/j.jtha.2025.05.014

Xiaoying Wang, Aizhen Yang, Shuyi Huang, Zhenzhen Zhao, Futian Ma, Yi Lu, Yujie Guo, Yan Wang, Yi Wu, Jingyu Zhang

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引用次数: 0

Abstract

Background: Thrombomodulin (TM) binds thrombin forming a thrombin-TM complex, thereby regulating the balance between coagulation and fibrinolysis. We found a proband carrying compound heterozygous mutations (c.754T>G, p.C252G and c.840C>A, p.C280X) in EGF-1 of THBD gene resulting into TM deficiency.

Objectives: To explore the molecular mechanism underlying the anticoagulant defect caused by C252G and C280X mutations.

Results: A 5-year-old Chinese boy with lifelong large ecchymosis due to TM deficiency showed marked hypofibrinogenemia with significant increased fibrinogen/fibrin degradation products, D-dimer, thrombin-antithrombin complex, and plasmin-α2 plasmin inhibitor complex, indicating a disseminated intravascular coagulation (DIC)-like microcirculatory thrombosis-bleeding syndrome. The proband carried heterozygous mutations (C252G and C280X) in THBD gene. In HEK293T cells transfected with TM-wild-type (WT), TM-C252G and TM-C280X cDNAs, both TM-WT and TM-C252G were comparably expressed on cell surface, while TM-C280X was not expressed due to the substitution of c.840C with A leading to a stop codon formation. The recombinant TM (rTM) carrying C252G mutation in both the extracellular domain (rTM-EC/C252G) and the membrane-penetrating type exhibited attenuated inhibitory effect on thrombin generation compared to rTM-WT. Moreover, rTM-EC/C252G exhibited lower activation of thrombin catalytic protein C and thrombin activatable fibrinolysis inhibitor (TAFI) than rTM-EC/WT, which may enhance coagulation and fibrinolysis. Protein conformation heatmap analysis revealed that rTM-EC/C252G mutant induced TM structural changes with >25% relative uptake differences compared to rTM-EC/WT.

Conclusion: We identified two novel TM variants (C252G and C280X) associated with DIC-like thrombosis-bleeding syndrome, providing the first genetic evidence for the critical role of Cys252-Cys265 in maintaining the structure and function of TM.

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血小板调节蛋白EGF-1结构域的新型p.C252G和p.C280X突变导致血栓形成-出血综合征。

背景：凝血调节蛋白（thromomodulin， TM）与凝血酶结合形成凝血-TM复合物，从而调节凝血和纤溶之间的平衡。我们发现一个先证者携带THBD基因EGF-1复合杂合突变（c.754T>G, p.C252G和c.840C> a, p.C280X）导致TM缺乏。目的：探讨C252G和C280X基因突变导致抗凝血功能缺陷的分子机制。结果：一名5岁的中国男孩因TM缺乏导致终身大瘀斑，表现为明显的低纤维蛋白原血症，纤维蛋白原/纤维蛋白降解产物、d -二聚体、凝血酶-抗凝血酶复合物和纤溶酶-α2纤溶酶抑制剂复合物显著升高，提示弥散性血管内凝血（DIC）样微循环血栓形成-出血综合征。先证者携带THBD基因杂合突变（C252G和C280X）。在转染tm -野生型（WT）、TM-C252G和TM-C280X cdna的HEK293T细胞中，TM-WT和TM-C252G在细胞表面均有相当程度的表达，而TM-C280X由于c.840C被A取代导致停止密码子的形成而未表达。与rTM- wt相比，在胞外结构域（rTM- ec /C252G）和穿膜型同时携带C252G突变的重组TM （rTM）对凝血酶产生的抑制作用减弱。与rTM-EC/WT相比，rTM-EC/C252G凝血酶催化蛋白C和凝血酶可活化纤维蛋白溶解抑制剂（TAFI）的活性较低，这可能促进凝血和纤维蛋白溶解。蛋白质构象热图分析显示，与rTM-EC/WT相比，rTM-EC/C252G突变体诱导TM结构变化，相对摄取差异为bb0.25%。结论：我们发现了两个新的TM变异（C252G和C280X）与dic样血栓形成-出血综合征相关，为Cys252-Cys265在维持TM结构和功能中的关键作用提供了第一个遗传学证据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Thrombosis and Haemostasis 医学-外周血管病

CiteScore

24.30

自引率

3.80%

发文量

321

审稿时长

1 months

期刊介绍： The Journal of Thrombosis and Haemostasis (JTH) serves as the official journal of the International Society on Thrombosis and Haemostasis. It is dedicated to advancing science related to thrombosis, bleeding disorders, and vascular biology through the dissemination and exchange of information and ideas within the global research community. Types of Publications: The journal publishes a variety of content, including: Original research reports State-of-the-art reviews Brief reports Case reports Invited commentaries on publications in the Journal Forum articles Correspondence Announcements Scope of Contributions: Editors invite contributions from both fundamental and clinical domains. These include: Basic manuscripts on blood coagulation and fibrinolysis Studies on proteins and reactions related to thrombosis and haemostasis Research on blood platelets and their interactions with other biological systems, such as the vessel wall, blood cells, and invading organisms Clinical manuscripts covering various topics including venous thrombosis, arterial disease, hemophilia, bleeding disorders, and platelet diseases Clinical manuscripts may encompass etiology, diagnostics, prognosis, prevention, and treatment strategies.