2种新的凝血因子V基因突变导致的遗传性凝血因子V缺乏症

目的 对一个遗传性凝血因子V缺乏症家系进行凝血因子V（FV）基因突变的检测。方法 经用活化部分凝血活酶时间（APTT）,凝血酶原时间（PT）及FV促凝活性（FV：C）和FV抗原（FV：Ag)测定进行表型诊断;用PCR法对先证者（女,16岁）的FV基因25个外显子及其侧翼序列进行扩增。PCR产物纯化后直接测序,检测其基因突变。突变位点经限制笥内切酶分析证实。108名健康献血者作对照。结果 先证者APTT126.6s,PT42.8s,FV:C0.3%;FV:Ag1.3%,FⅡ：C,FVⅡ：C,FVⅢ：C,FIX：C,FX：C和Fbg均在正常范围内：FV外显子区共发现5个与GeneBankZ99572序列不同的位点,其中突变位点为位于第8外显子区的G1348T和位于第14外显子区的4887-8delG。家系分析表明前导致先证者FV缺乏的原因。这是2个导致遗传性FV缺乏症的新的FV基因突变位点。

Two novel factor V gene mutations associated with congenital coagulation factor V deficiency,study of one pedigree

OBJECTIVE: To discover the gene mutations of a pedigree with inherited factor V (FV) deficiency. METHODS: The activated partial thromboplastin time (APTT), prothrombin time (PT), FV activity (FV:C) and FV antigen test were adopted for phenotype diagnosis. The genomic DNA was extracted from the peripheral blood of the 16-year-old propositus, female. All the 25 exons and their flanks in the FV gene of the propositus were amplified by polymerase chain reaction (PCR). The PCR products were screened by direct sequencing and the mutations were further confirmed by restricted enzyme digestion. Six persons in the pedigree (grandfather, grandmother, father, mother, uncle, and aunt) were examined too. 108 healthy blood donors were used as controls. RESULTS: The APTT, PT, FV:C, and FV:Ag of the propositus were 126.6s, 42.8s, 0.3% and 1.3% respectively. The Fbg and FII, FVII, FVIII, FIX, FX activities were in normal range. FV:C of the members of the pedigree was 36% - 70%, and the FV:Ag of the pedigree members was 26.4% - 45.3% that of the mixture of 30 normal plasma samples. Taking the GeneBank Z99572 sequence as the reference, totally five variations in the FV gene were found in the propositus. The mutations, A1348G and 4887 approximately 8delG, were traced to her father and her mother respectively. No 1348G-->T mutation was found in the 108 controls. CONCLUSION: The FV deficiency of the propositus is caused by missense mutation of G1348T and frameshift mutation of 4887 approximately 8delG, which haven't been identified previously.