遗传性血管性水肿C1INH基因1440V变异及其对结构的影响

目的 通过基因测序了解遗传性血管性水肿(HAE)患者C1酯酶抑制剂(C1INH)基因第八外显子的变异情况.方法 从HAE患者外周血白细胞中提取基因组DNA,PCR扩增第八外显子片段后插入pUC19质粒载体冉转化入感受态大肠杆菌TG1菌株,培养扩增质粒DNA,提取纯化后进行基因测序.将患者血清进行SDS-PAGE及Westem印迹,以了解该变异对CIINH结构的可能影响.结果 在1例I型HAE患者的第八外显子中发现一个变异位点,16776A＞G,致440位的异亮氨酸突变成缬氨酸(1440V),SDS-PAGE及Westem印迹显示该患者血清中C1INH全部表现为96 000片段而非正常的105 000片段.结论 1440v是一个新的C1INH基因变异,位于C1INH反应中心环的P4位,变异可能导致C1INH分子构象发生改变.

I440V mutation in C1 esterase inhibitor gene in a patient with hereditary angioedema and its influence to the structure of C1 esterase inhibitor

Objective To assess the mutation in exon 8 of C1 esterase inhibitor(C1INH)gene in a patient with hereditary angioedema(HAE).Methods Genomic DNA was extracted from a female patient with HAE as well as her mother and a normal human control.The fragment of exon 8 of C1INH gene was amplified by PCR and inserted into plasmid carrier pUC19 with the help of ligase.Then,the recombinant plasmid was transformed into competent cells of E coli TG1 strains.After culture of positive transformant,plasmid DNA Was extracted and subjected to sequencing.SDS-PAGE and We:stem blot were performed on the sera of the patient to detect the concentration and function of C1INH protein.Results An A1677G mutation at exon 8 of C1INH gene.which resulted in a substitution of isoleucine to valine at codon 440,Was found in the patient who SUfiered from HAE type I.Additionally.SDS-PAGE and Western blot revealed that the molecular weight of C1INH protein was 96 000.but not 105 000 observed in noHnal human control.Conclusion The newly identified mutation 1440V.which is located at P4 residue of reactive center loop in C1INH.may result in conformational alteration of C1INH.