姐妹2人同患家族性高胆固醇血症家系LDL-R基因突变分析

The LDL-R gene mutation analysis in sibling sisters of familial hypercholesterolemia

目的:对临床确诊的家族性高胆固醇血症(FH)两姐妹及其家系成员进行低密度脂蛋白受体(LDL-R)基因突变分析,探讨其发病机制。方法:提取患者外周血基因组DNA,聚合酶链反应分别扩增启动子和18个外显子片断,采用单链构象多态性(PCR-SSCP)结合银染技术,对异常电泳条带进行核苷酸序列分析。结果:姐妹2人及其父亲,叔叔,祖母均发现LDL-R基因第13外显子存在一个错义突变,与GeneBank对照证实第1879位G→A碱基置换,氨基酸的改变为丙氨酸→苏氨酸(A606T突变),其母亲和女儿经测序并未发现此突变位点。结论:姐妹2人均为LDL-R基因存在A606T杂合错义突变,并均来自其父系亲属;可能是该家系发病的分子基础。

Objective：To screen the point mutation of low density lipoprotein receptor（LDL-R） gene in Chinese familial hypercholesterolemia （FH） patients, we use PCR single strand conformation polymorphism（PCR-SSCP）,and discuss the molecular pathologic mechanism of FH.Method：A patient with the clinical phenotype of FH as well as her family have been investigated for mutations of promoter and all eighteen exons of LDL-R gene. Screening was carried out by using Touch-down PCR, agarose gel electrophoresis and PCR-SSCP, combined with DNA sequence analysis. Then the result were compared with that in FH GeneBank. Result：A missense mutation in LDL-R extron 13 was detected in 4 members of the family. Compaired with the GeneBank, a G→A base substitution was found in 1？879 site,and it＇s proved the A606T mutation. Conclusion：A heterozygosis G→A missense mutation in LDL-R gene was found in the twin sisters. The change of the missense mutation in LDL-R extron 13 may come from their father.