Su Kankan, Jin Yanhui, Miao Zhihai, Cheng Xiaoli, Yang Lihong, Wang Mingshan
a Department of Clinical Laboratory , The First Affiliated Hospital of Wenzhou Medical University , China.
Hematology. 2017 Jul;22(6):380-385. doi: 10.1080/10245332.2017.1287332. Epub 2017 Feb 14.
We study the phenotype and genotype of a novel gene mutation of factor II (FII) that leads to dysprothrombinemia, and do the meta-analysis to illuminate its molecular pathogenesis. It will further contribute to our comprehension of the pathogenesis of this type of disease.
The prothrombin time (PT), activated partial thromboplastin time (APTT) and the activities of other factors were determined by the one-stage clotting method. The prothrombin antigen was measured with enzyme-linked immunosorbent assay (ELISA). Function of the mutant protein was evaluated by thrombin generation tests. Potential mutations in exons, exon-intron boundaries and 5', 3' untranslated sequences of prothrombin gene were screened by polymerase chain reaction and direct sequencing. Suspected mutations were confirmed by reverse sequencing. The structure change of this protein was analyzed by model and bioinformatics analyses.
Phenotypic analysis revealed that the proband had an obviously prolonged PT, APTT, reduced prothrombin activity but normal antigen levels. The other tests were normal. Sequencing analysis detected a homozygous g.26329T>G in the catalytic domain resulting in p.Tyr510Asp. His parents and uncle were heterozygous for this mutation. The thrombin generation test showed that the mutant protein had obstacles in thrombin generation. Bioinformatics and model analyses illuminated that the mutation will be probably damaging and perturbing the structure of Na+-binding site, which will affect the activation of prothrombin.
This was the first report of such a mutation in the position which was associated with dysprothrombinemia.
我们研究导致异常凝血酶原血症的凝血因子II（FII）新基因突变的表型和基因型，并进行荟萃分析以阐明其分子发病机制。这将进一步有助于我们理解此类疾病的发病机制。
采用一期凝血法测定凝血酶原时间（PT）、活化部分凝血活酶时间（APTT）及其他因子活性。用酶联免疫吸附测定法（ELISA）检测凝血酶原抗原。通过凝血酶生成试验评估突变蛋白的功能。采用聚合酶链反应和直接测序法筛查凝血酶原基因外显子、外显子-内含子边界及5'、3'非翻译序列中的潜在突变。通过反向测序确认可疑突变。通过模型和生物信息学分析该蛋白的结构变化。
表型分析显示，先证者PT、APTT明显延长，凝血酶原活性降低但抗原水平正常。其他检查均正常。测序分析在催化结构域检测到纯合的g.26329T>G，导致p.Tyr510Asp。其父母和叔叔为该突变的杂合子。凝血酶生成试验表明，突变蛋白在凝血酶生成方面存在障碍。生物信息学和模型分析表明，该突变可能具有破坏性并扰乱Na+结合位点的结构，从而影响凝血酶原的激活。
这是首次报道该位置与异常凝血酶原血症相关的此类突变。
