6个遗传性凝血因子Ⅹ缺陷症家系的表型与基因型诊断

Phenotype and genotype diagnosis of 6 pedigrees with inherited coagulation factor Ⅹ deficiency

目的:探讨6个遗传性凝血因子Ⅹ(factor Ⅹ, FⅩ)缺陷症家系的分子发病机制,并采用凝血酶生成试验(thrombin generation test, TGT)评估FⅩ缺陷症患者的出血风险。方法:收集6例先证者及相关家系成员的临床资料,凝固法检测内源性、外源性以及共同途径激活的FⅩ活性(FⅩ∶C),酶联免疫吸附试验双抗体夹心法检测FⅩ抗原(FⅩ∶Ag),采用蛋白印迹法检测血浆中的FⅩ相对分子质量及含量,直接测序法检测FⅩ基因(F10)突变,采用TGT检测6例先证者及部分家系成员血浆中的凝血酶生成。结果:在6例先证者中共发现了10种F10突变,其中5种(p.Cys246Ser, p.Tyr319Cys, p.Leu252Phe, p.Arg313Gln以及IVS5-2A>G)为新突变,其余5种(p.Phe71Ser, p.Val338Met, p.Gly406Ser, p.Gly365Ser, p.Cys151Arg)为已报道突变。TGT显示凝血酶生成潜力(endogenous thrombin potential, ETP)及峰值这2个参数与FⅩ缺陷症患者临床出血表现的严重程度具有一定关联。结论 :共发现5种F10基因新突变;5例遗传性FⅩ缺陷症患者由F10双杂合突变所致,1例由F10单杂合突变所致;在浓度为1 pM(1 pmol/L)组织因子(tissue factor,TF)激活下的TGT中,测得的ETP及峰值这2个参数可用于评估FⅩ缺陷症患者的出血倾向,对于了解该病患者的临床出血风险有一定的参考价值。

Objective: To investigate the molecular pathogenesis of 6 pedigrees with inherited coagulation factor Ⅹ(F Ⅹ) deficiency and to assess the bleeding risk in patients with inherited F Ⅹ deficiency by thrombin generation test(TGT).Methods: Clinical data of the 6 pedigrees were collected. The FⅩ coagulation activity(FⅩ:C) was tested by clotting test and F Ⅹ antigen(F Ⅹ :Ag) was detected by double antibody sandwich enzyme-linked immunosorbent assay(ELISA). The concentration of FⅩ in plasma was measured with Western blotting. The FⅩ gene(F10) mutation was analyzed by direct sequencing. Thrombin generation(TG) in six patients and some family members was measured using TET.Results: Ten F10 mutations were identified in 6 probands, five of which(p.Cys 246 Ser, p.Tyr 319 Cys, p.Leu 252 Phe,p.Arg 313 Gln and p. IVS5-2 A>G) were novel and the other five(p.Phe71 Ser, p.Val 338 Met, p.Gly 406 Ser, p.Gly 365 Ser and p.Cys 151 Arg) had been previously reported. TGT showed that endogenous thrombin potential(ETP) and peak height(Peak) had certain correlation with bleeding severity of FX-deficient patients. Conclusions: Five noval mutations of F Ⅹare identified. Five patients were resulted from compound heterozygous F10 mutations, while the remaining one is caused by one heterozygous F10 mutation. TGT parameters including ETP and Peak could be used to assess the bleeding risk in patients with FⅩ deficiency, and TGT might serve as a useful laboratory tool to monitor the risk of bleeding.