CAJ | 학술논문

目的对1个遗传性凝血因子Ⅻ(coagulation factorⅫ,FⅫ)缺陷症家系进行基因突变检测,了解其分子发病机制.方法检测先证者及其家系成员的活化部分凝血活酶时间(activated partial thromboplastin time,APTT)、血浆FⅫ活性(FⅫactivity,FⅫ∶C)和血浆FⅫ抗原(FⅫantigen,FⅫ∶Ag)含量等表型指标;用DNA测序法检测先证者FⅫ基因的全部14个外显子及侧翼序列,发现突变位点则予反向测序证实;针对先证者的突变位点,对该家系成员进行相应的基因突变检测.结果先证者和其儿子APTT、FⅫ∶C和FⅫ∶Ag明显异常,分别为121.5 s、5％、6.8％和98.5s、9％、12.2％,同时纤溶酶原活性(plasminogen activity,PLG∶A)均略高于正常参考值范围;其他家系成员中,除其小女儿和外孙的FⅫ∶C略低外(分别为64％和60％),其他成员FⅫ∶C均在正常参考值范围(72％～113％)内.先证者和其儿子的FⅫ基因第13外显子发生了g.8597G＞A杂合突变,导致p.Asp538Asn错义突变,FⅫ启动子区46C/T多态性均为TT基因型;其他4名家系成员中均未见g.8597G＞A杂合突变,有3名成员启动子区为46C/T位点为CT基因型和1名成员为TT基因型.结论该家系中发现的FⅫ基因第13外显子g.8597G＞A突变为一种新突变.此杂合突变导致的p.Asp538Asn错义突变是该家系遗传性FⅫ缺陷症的分子发病机制;p.Asp538Asn和46TT基因型与家系成员的FⅫ水平明显降低有关.
목적 대1개유전성응혈인자Ⅻ(coagulation factorⅫ,FⅫ)결함증가계진행기인돌변검측,료해기분자발병궤제.방법 검측선증자급기가계성원적활화부분응혈활매시간(activated partial thromboplastin time,APTT)、혈장FⅫ활성(FⅫactivity,FⅫ∶C)화혈장FⅫ항원(FⅫantigen,FⅫ∶Ag)함량등표형지표;용DNA측서법검측선증자FⅫ기인적전부14개외현자급측익서렬,발현돌변위점칙여반향측서증실;침대선증자적돌변위점,대해가계성원진행상응적기인돌변검측.결과 선증자화기인자APTT、FⅫ∶C화FⅫ∶Ag명현이상,분별위121.5 s、5％、6.8％화98.5s、9％、12.2％,동시섬용매원활성(plasminogen activity,PLG∶A)균략고우정상삼고치범위;기타가계성원중,제기소녀인화외손적FⅫ∶C략저외(분별위64％화60％),기타성원FⅫ∶C균재정상삼고치범위(72％～113％)내.선증자화기인자적FⅫ기인제13외현자발생료g.8597G＞A잡합돌변,도치p.Asp538Asn착의돌변,FⅫ계동자구46C/T다태성균위TT기인형;기타4명가계성원중균미견g.8597G＞A잡합돌변,유3명성원계동자구위46C/T위점위CT기인형화1명성원위TT기인형.결론 해가계중발현적FⅫ기인제13외현자g.8597G＞A돌변위일충신돌변.차잡합돌변도치적p.Asp538Asn착의돌변시해가계유전성FⅫ결함증적분자발병궤제;p.Asp538Asn화46TT기인형여가계성원적FⅫ수평명현강저유관.
Objective To identify potential mutation underlying hereditary coagulation factor Ⅻ (F Ⅻ) deficiency in a pedigree and explore its molecular pathogenesis:Methods Activated partial thromboplastin time (APTT),FⅫ activity (FⅫ ∶ C) and FⅫ antigen(FⅫ ∶ Ag) and other coagulant parameters of the proband and 5 family members were measured.Potential mutations in the 14 exons and intron-exon boundaries of the FⅫ gene were screened with polymerase chain reaction (PCR) and direct DNA sequencing.Suspected mutations were confirmed with reverse sequencing.Corresponding PCR fragments from other family members were also sequenced.Results APPT of the proband and his son were significantly prolonged to 121.5 s and 98.5 s,respectively.FⅫ ∶ C and FⅫ ∶ Ag of the proband and his son have reduced to 5％,6.8％ and 9％,12.2％,respectively.Plasma plasminogen activity (PLG ∶ A) in both individuals was slightly higher than the normal reference range.FⅫ ∶ C of his second daughter and grandson were slightly reduced to 64％ and 60％.FⅫ ∶ C of the other family members were all in the normal range (72 ％-113 ％).A heterozygous missense mutation;g.8597G＞ A,was identified in exon 13 of the FⅫⅫgene in the proband,which resulted in an p.Asp538Asn substitution.For the promoter regions of the FⅫgene,the genotype of the proband was 46TT.The same mutations and 46T/T were also found in the proband's son but not in other members of the family.The genotypes of the proband's spouse,eldest daughter and grandson were 46CT,and his second daughter was 46TT.Conclusion The heterozygous mutation of g.8597G＞A identified in exon 13 of FⅫ gene is a novel mutation.Heterozygous p.Asp538Asn mutation and 46TT in the FⅫ gene can cause hereditary FⅫ deficiency,which was probably responsible for the low FⅫ concentrations in this pedigree.