8例遗传性凝血因子Ⅶ缺陷症患者基因诊断与临床特征分析

Clinical characteristics and genetic diagnosis of hereditary FⅦ deficiency: Analysis of 8 patients

目的:探讨8例遗传性凝血因子Ⅶ(FⅦ)缺陷症患者的基因突变类型与临床特征。方法:采用一期法检测患者的FⅦ活性(FⅦ:C),用双抗体夹心酶联免疫吸附法检测其FⅦ抗原(FⅦ:Ag)水平;并抽提先证者及其家系成员的外周血基因组DNA,PCR扩增FⅦ基因所有外显子及其侧翼序列,采用DNA直接测序进行基因分析。结果:在8例遗传性FⅦ缺陷症患者中发现9种类型的基因突变,包括3种剪切位点突变和6种错义突变,其中p.Glu76(16)Gln和p.Gly343(283)Asp这2种突变为国际首次报道。1例患者为p.Tyr128(68)Cys纯合突变,其FⅦ:C<1%,FⅦ:Ag为1%,临床表型为重度出血;另1例为p.Cys389(329)Gly纯合突变,其FⅦ:C为2.7%,FⅦ:Ag为50%,为交叉反应物质阳性(CRM+)的FⅦ缺陷症,其临床无出血表现。4例患者携带FⅦ基因双杂合突变,分别为IVS5-1G>A和p.Arg350(290)Cys、IVS5-1G>A和p.Cys389(329)Gly、IVS1a+5G>A和p.Glu76(16)Gln、IVS1a+5G>A和p.Gly343(283)Asp突变,其相应的FⅦ:C分别为4.9%、1.8%、2.2%和1.5%,患者临床出血症状较轻或无临床出血表现。2例患者携带单杂合突变,分别为p.Arg337(277)Cys和IVS5-2A>G,其FⅦ:C分别为4.5%和1.2%,前者无临床出血表现,后者有反复鼻出血。结论:在8例遗传性FⅦ缺陷症患者中发现了9种类型的FⅦ基因突变,其中2种为新发现突变。IVS5-1G>A、IVS1a+5G>A、p.Cys389(329)Gly突变在8例患者中较常见,而FⅦ基因突变及FⅦ:C情况与患者的临床表型间无相关性。

Objective： To investigate mutations of the coagulation factor VII（FVg） gene and the clinical features in 8 patients with hereditary FVII deficiency. Methods： FVII coagulation activity （FV]I：C） and antigen （FVU：Ag） were assayed by one-stage clotting test and double-antibody sandwich ELISA , respectively. Genomic DNA was extracted from peripheral blood of the proband and pedigree family members. All the exons and flanking sequences of FVIIgene were amplified by polymerase chain reaction （PCR） and gene analysis was performed by direct sequencing. Results： Nine different mutations were identified in 8 unrelated probands, including 3 splice site mutations and 6 miss sense mutations, and two （p.Glu76 （16）Gln, p.Gly343 （283）Asp） of them were the first reported in literature. One patient had p.Tyr128 （68）Cys homozygous mutation, FVII ：C 〈1%, FVII ：Ag=1%, with a clinical feature of severe bleeding. Another patient had p.Cys389（329）Gly homozygous mutation, FVII：C=2.7% , FVII：Ag=50%, was a case of CRM （cross reacting material） positive FVII deficiency syndrome with no bleeding presentation clinically. Four patients had double heterozygous mutations IVS5-1G〉A and p.Arg350（290）Cys, IVS5-1G〉A and p.Cys389（329）Gly, IVSla＋SG〉A and p.Glu76（16）Gln, IVSla＋SG〉A and p.Gly343（283） Asp） with F VII ：C =4.9%, 1.8%, 2.2% and 1.5%, respectively, and presenting as mild bleeding or asymptomatic. Two patients had mono-heterozygous mutation： IVS5-2A 〉G mutation, F VII ：C = 1.2%, with repeated nose-bleeding in one patient, and p.Arg337 （277）Cys mutation, FVII：c=4.5%, with no clinical bleeding presentation in the other. Conclusions： Nine types of FVII gene mutations are identified in 8 unrelated probands with hereditary FVII deficiency, and two of them are the first reported in literature. IVS5-1G〉A, IVSla＋5G〉A, p.Cys389 （329）Gly are the commonly seen mutations in Chinese Han patients with F VII deficiency, and FVIIgene mutation has no significant correlation with F VII ：C and clinical phenotypes.