凝血因子Ⅹ基因复合杂合错义突变Gla26Lys和Ser425Pro导致因子Ⅹ缺陷症

Severe coagulation factor Ⅹ deficiency caused by two de novel heterozygous missense mutations in factor Ⅹ gene

目的:检测1例凝血因子Ⅹ(FⅩ)缺陷患者的基因突变。方法:用活化部分凝血活酶时间(APTT)、凝血酶原时间(PT)及FⅩ促凝活性(FX:C)等测定进行表型诊断;用PCR法对其F10基因8个外显子及其侧翼序列和5′端非翻译区(5′UTR)序列进行扩增,PCR产物纯化后直接测序,检测其基因突变。突变位点经限制性内切酶分析排除多态性。结果:患者APTT100.0s、PT46.6s、FX:C2.4%。位于F10基因Exon2内杂合性G8394A错义突变导致Gla(GAG)26Lys(AAG);位于Exon8内的杂合性T28262C错义突变导致Ser(UCC)425Pro(CCC)。限制性内切酶分析排除Ser425Pro为多态性。结论:复合杂合性错义突变Gla26Lys和Ser425Pro可能是导致该例患者FⅩ缺陷症的原因。这是2个新的导致FX缺陷症的F10基因突变。

Objective：To identify gene mutations of a patient with coagulation factor X （FX） deficiency. Methods：The activated partial thromboplastin time（APTT）, prothrombin time（PT）, thrombin time, the activities of F Ⅱ ,FV,FⅦ,FⅧ ,FⅨ and FⅩ （F Ⅱ ： C, FⅦ ： C, FⅧ ： C, FⅨ ： C and FⅩ ： C） were performed for phenotypic diagnosis. The genomic DNA was extracted from the peripheral blood of the proband and all the 8 exons and their flanks of F10 gene were amplified by polymerase chain reaction （PCR）. The PCR products were screeed by direct sequencing and the mutations were further confirmed by restricted enzyme digestion to eliminate the possibility of polymorphism. Results：APTT,PT,TT,FⅡ ：C,FⅤ ：C,FⅦ ：C,FⅧ：C,FⅨ ：C and FX ：C of the proband were 100 s, 46.6s, 13.9 s, 60.0%, 89%, 59%, 81.5%, 63% and 2.4%, respectively. Compound heterozygous missense mutations in F10 gene were identified in the proband. One was G to A in exon 2, leading Gla（GAG） 26 to Lys（AAG） in the Gla domain; another was T to C in exon 8, resulting the substitution of Ser（UCC）425 by Pro（CCC） in the catalytic domain. Conclusion：These two de novel heterozygous missense mutations might be the molecular mechanisms of coagulation factor X deficiency for the patient.