1例家族性高胆固醇血症患者低密度脂蛋白受体基因新突变体功能研究  

Functional analysis on novel mutants of low density lipoprotein receptor gene in a familial hypercholesterolemia patient

作　　者：王海红[1,2] 王春梅[1,3] 徐胜媛[1,2] 孙立元[1,2] 关啸 鲁昆[1,2] 潘晓冬[1,4] 刘飒[1,4] 杨士伟[1,2] 王绿娅[1,2] 

机构地区：[1]首都医科大学附属北京安贞医院 [2]北京市心肺血管疾病研究所动脉硬化室,北京100029 [3]北京市心肺血管疾病研究所三十五病房,北京100029 [4]北京市心肺血管疾病研究所实验中心,北京100029

出　　处：《临床检验杂志》2014年第5期324-328,共5页Chinese Journal of Clinical Laboratory Science

基　　金：国家自然科学基金(81170810;81271923);北京市自然科学基金(7112022)

摘　　要：目的分析基因突变对低密度脂蛋白受体(LDLR)功能的影响,探讨其对家族性高胆固醇血症(FH)的可能致病机制。方法对1名FH患者进行基因检测,构建真核细胞表达载体,经定点诱变获得突变受体质粒,并将突变受体质粒转染入人胚肾(HEK293)细胞中,用激光共聚焦显微镜(CLSM)观察突变蛋白细胞定位,用流式细胞术检测突变蛋白表达及内吞活性变化。结果基因测序显示该名患者发生了LDLR基因Y398X突变;CLSM结果显示突变蛋白部分滞留于内质网中;流式细胞术结果显示细胞表面LDLR表达量减少至5.5%,内吞活性减少至20.1%。结论在临床确诊的FH患者中检测到LDLR致病性基因Y398X突变,在中国为首次报道。该突变造成LDLR转运缺陷,从而导致血浆中胆固醇代谢障碍,继而诱发FH的发生。Objective To investigate the effects of gene mutation on the function of low density lipoprotein receptor（ LDLR） and explore the pathogenesis of familial hypercholesterolemia（ FH） for providing reasonable treatment. Methods The gene detection of a FH patient was conducted. The eukaryotic expression vector was constructed and the plasmid of mutational receptors was obtained by sitedirected mutagenesis and was transfected into human embryo kidney cells（ HEK-293）. The intracellular localization of the mutant proteins was observed by confocal laser-scanning microscope（ CLSM）. The expression of mutant proteins and the changes of internalization activity were detected by flow cytometry. Results Genetic sequencing revealed Y398X mutation of LDLR gene was detectable in the FH patient. The results of CLSM showed that the LDLR proteins partly retained in the endoplasmic reticulum. Flow cytometry showed that the expression of the mutant LDLR on the cell surface were reduced to 5. 5% and the internalization activity were reduced to 20. 1%. Conclusion A novel Y398X mutation of LDLR gene was detectable in a clinically confirmed FH patient,which has not been reported in China. The LDLR mutant may result in defective transportation,which lead to reduction of cholesterol clearance in plasma and induce high cholesterol in the pathogenesis of FH.

关 键 词：家族性高胆固醇血症 低密度脂蛋白受体 基因突变 功能研究 

分 类 号：R725.4[医药卫生—儿科] R446[医药卫生—临床医学]