CAJ | 학술논문

目的分析中国儿童家族性高胆固醇血症低密度脂蛋白受体基因突变,并建立筛查该基因突变的方法。方法以一家两患儿及其父母的基因组DNA为模板，用聚合酶链反应（PCR）扩增该基因的启动子和全部18个外显子。用温度梯度凝胶电泳（TGGE）分析检测PCR产物，对电泳结果异常者进行DNA测序。结果平行TGGE发现，两患儿第13外显子存在一纯合突变，其父母此外显子存在杂合突变。DNA测序证实两患儿第13外显子发生Ala606→Thr纯合错义突变，其父母均为此Ala606→Thr杂合突变。结论此家系家族性高胆固醇血症患者的LDL受体基因存在Ala606→Thr突变。TGGE结合DNA测序法的建立可用于本症的基因诊断。
목적분석중국인동가족성고담고순혈증저밀도지단백수체기인돌변,병건립사사해기인돌변적방법。방법이일가량환인급기부모적기인조DNA위모판，용취합매련반응（PCR）확증해기인적계동자화전부18개외현자。용온도제도응효전영（TGGE）분석검측PCR산물，대전영결과이상자진행DNA측서。결과평행TGGE발현，량환인제13외현자존재일순합돌변，기부모차외현자존재잡합돌변。DNA측서증실량환인제13외현자발생Ala606→Thr순합착의돌변，기부모균위차Ala606→Thr잡합돌변。결론차가계가족성고담고순혈증환자적LDL수체기인존재Ala606→Thr돌변。TGGE결합DNA측서법적건립가용우본증적기인진단。
Objective Familial hypercholesterolemia (FH), an autosomaldominant disorder caused by mutations in the low density lipoprotein receptor (LDLR) gene, is closely associated with premature development of cardiovascular disease. In this study, we applied a gene screening method and investigated LDLR gene mutations in children with familial hypercholesterolemia in China. Methods The proband, a 14-year-old girl, was given a clinical diagnosis of FH based on a markedly increased concentration of plasma cholesterol(15.4 mmol/L ), presence of tendon xanthomata. The proband′s sister, who was 12 years old, also presented the same clinical manifestation. However, their parents had had no clinical signs of FH. Genomic DNA were extracted from the two children and their parents in the family. Promoter region and all of the 18 exons of LDLR gene including the intron-exon boundary were amplified by polymerase chain reaction (PCR) and were analyzed by Temperature gradient gel electrophoresis (TGGE). The PCR products show abnormal patterns by TGGE were sequenced directly. ResultsA homozygous mutation at exon 13 of the proband was found by parallel TGGE. Homozygous and heterozygous mutations were also found in the family by parallel TGGE. A missense mutation (Ala606→Thr) in exon 13 of LDLR gene was identified by DNA sequencing．The two children had homozygous mutation; their parents were heterozygous mutation. It was first reported that the homozygous Ala606→Thr mutation was found in the mainland of China. Conclusion The newly identified mutation cosegregated in the family members and were thought to be causal for the FH phenotype. Molecular genetic analysis of the gene for the LDL receptor in affected families can contribute towards early assessment for the diagnosis of FH and thus to prevention of life threatening cardiovascular episodes in asymptomatic subjects. TGGE combined with DNA sequencing can be used in the genetic diagnosis of FH.