一个纯合家族性高胆固醇血症家系低密度脂蛋白受体基因突变的检测  

Gene mutations in low-density lipoprotein receptor in one Chinese padigree with homozygous familial hypercholesterolemia

作　　者：丁军发[1] 郑芳[1] 周新[1] 程小欢[1] 马俊婕[1] 陈永梅[1] 

机构地区：[1]武汉大学中南医院基因诊断中心,430071

出　　处：《中华检验医学杂志》2008年第7期774-779,共6页Chinese Journal of Laboratory Medicine

基　　金：2005年新世纪人才基金资助项目（NCET-05-0621）;湖北省杰出青年基金资助项目（2006ABB009）

摘　　要：目的检测家族性高胆固醇血症（familial hypercholesterolemia，FH）患者低密度脂蛋白受体（low density lipoprotein receptor，LDLR）的基因突变。方法提取家系中，临床通过典型特征和血脂检测诊断为家族性高胆固醇血症患者的基因组DNA，首先检测载脂蛋白B100（apoB100）基因R3500Q突变，以排除家族性apoB100缺陷症（Familial defective apoB100，FDB）。然后用降落聚合酶链反应（TOUCH-DOWN PCR）扩增该基因的启动子和全部18个外显子，再用单链构象多态性（SSCP）方法分析PCR产物，并对电泳结果异常者进行DNA测序分析。用ANTHEPROT 5．0软件对突变LDLR进行二级结构分析，然后对突变LDLR进行SWISS MODEL在线三级结构预测。结果通过SSCP和DNA测序发现该家系患者13号外显子存在A606T的纯合突变，采用ANTHEPROT 5．0软件的GORⅠ法对突变型和野生型蛋白质进行二级结构分析，可见突变蛋白的突变区域部分螺旋结构被转角结构和无规卷曲取代，其二级结构发生了改变。突变LDLR三级结构预测未发现主链结构的变化。结论结果表明，LDLR基因A606T的突变可能是此高胆固醇血症家系的致病原因所在。Objective To investigate low density lipoprotein receptor （LDLR）gene mutation in familial hypercholesterolemia （FH） patients. Methods The proband was given clinical diagnosis of homozygous FH based on marked features and blood lipid tests results. After apoB100R3500Q mutation was excluded, the promoter region and all of the 18 exons of LDLR gene were amplified by touch-down polymerase chain reaction （PCR）. The PCR products were analyzed by single-strand conformational polymorphism （SSCP）. The PCR products with abnormal single strands were sequenced directly. The secondary structures of the mutational and wild type proteins were analyzed and compared by ANTHEPROT5. 0, and then the tertiary structures of the mutant and wild type LDLR were predicted at SWISS MODEL homepage online. Results A homozygous mutation A606T at exon 13 of the patients was found by SSCP and confirmed by DNA sequencing. GOR Ⅰ method in ANTHEPROT5. 0 indicates that the random coils and turns would replace some helixes at the mutation site. The online prediction from the SWISS MODEL homepage indicates the backbone structure of the mutant LDLR has no difference from the wild type one. Conclusion The results suggest the A606T mutation of LDLR gene is the cause of the FH in this pedigree.

关 键 词：高胆固醇血症 家族性 受体 LDL 纯合子 突变 

分 类 号：R686[医药卫生—骨科学]